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All orders placed on our website are processed within 2-4 business days, from Monday to Friday, 8:00 AM – 6:00 PM Pacific Time (PT). Orders received after our daily cut-off time of 10:00 PM PT will be processed on the next business day. Please note that we do not process orders on weekends or public holidays.
Shipping Methods and Carriers
Zetlly partners exclusively with reputable shipping carriers to ensure timely delivery of your orders. We utilize:
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FedEx
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UPS
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USPS
The choice of carrier is determined by factors such as destination, weight, and delivery timeframe to provide optimal service.
Shipping Rates and Fees
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Free shipping is provided for all orders over $199.
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Orders under $199 will incur a flat-rate shipping fee of $7.99.
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All orders shipped within the United States will be subject to a sales tax charge of 5%.
Estimated Delivery Time
Once shipped, orders typically arrive within 6 to 10 business days. Our delivery times are from Monday to Friday, 8:00 AM – 6:00 PM Pacific Time (PT). Please allow additional time for deliveries to remote or rural locations.
Shipping Restrictions
Zetlly currently ships exclusively within the United States. At present, we do not offer international shipping or deliveries to P.O. boxes or APO/FPO addresses. Orders placed with addresses outside our designated delivery areas will be canceled, and refunds will be processed accordingly.
Tracking Your Order
Upon shipment, customers will receive a confirmation email containing tracking information. You can track your order directly through the provided tracking link or by visiting the carrier’s official website:
Please allow up to 48 hours for tracking information to update in the carrier’s system.
Eligibility for Returns and Exchanges
We accept returns and exchanges within 30 days from the date your order is delivered. Items must be unused, in the original condition, and accompanied by the original packaging and receipt or proof of purchase.
How to Return or Exchange an Item
To initiate a return or exchange, please follow these steps:
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Contact our customer support at contact@zetlly.com with your order number and reason for return or exchange.
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Our team will respond within 24 hours to provide detailed instructions, including the specific Return Address for your shipment.
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Package your item securely and include all original packaging and proof of purchase.
Return shipments should be sent to: Blanq LLC 1201 South Hope Street Apt 2413, Los Angeles, CA 90015, USA
Return Conditions
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Items must be returned in their original condition, unworn, undamaged, and complete with all original packaging and documentation.
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Items returned without prior authorization or not meeting the above conditions may not qualify for a refund or exchange.
Return Shipping Costs
Customers are responsible for return shipping costs unless the return is due to our error or a defective product. We recommend using a trackable shipping service to ensure your return reaches us safely.
Non-Returnable Items
The following items cannot be returned:
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Digital products (e-books or downloadable content)
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Personalized or customized items
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Gift cards
Accepted Payment Methods
Zetlly accepts the following secure and widely trusted payment options:
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PayPal: Easily pay through your PayPal account, benefiting from secure transactions and buyer protection.
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Stripe: Pay securely using major credit and debit cards including Visa, MasterCard, American Express, and Discover via Stripe’s encrypted payment gateway.
Payment Security
At Zetlly, your security is our utmost priority. We utilize advanced encryption technologies and robust security protocols provided by PayPal and Stripe. All payment information entered on our site is encrypted using Secure Socket Layer (SSL) technology, ensuring your financial information remains private and secure throughout the transaction process.
Zetlly does not store any credit card or sensitive financial information directly on our servers, further enhancing the security and protection of your personal data.
Payment Process and Confirmation
Upon placing an order, your chosen payment method (PayPal or Stripe) will immediately process the transaction. You will receive an automated confirmation email shortly after your payment has been successfully completed, detailing your transaction and order summary.
Please retain this confirmation email for your records and reference in case of any inquiries or disputes.
The essential reference book on matrices�now fully updated and expanded, with new material on scalar and vector mathematics Since its initial publication, this book has become the essential reference for users of matrices in all branches of engineering, science, and applied mathematics.
In this revised and expanded edition, Dennis Bernstein combines extensive material on scalar and vector mathematics with the latest results in matrix theory to make this the most comprehensive, current, and easy-to-use book on the subject. Each chapter describes relevant theoretical background followed by specialized results. Hundreds of identities, inequalities, and facts are stated clearly and rigorously, with cross-references, citations to the literature, and helpful comments. Beginning with preliminaries on sets, logic, relations, and functions, this unique compendium covers all the major topics in matrix theory, such as transformations and decompositions, polynomial matrices, generalized inverses, and norms. Additional topics include graphs, groups, convex functions, polynomials, and linear systems. The book also features a wealth of new material on scalar inequalities, geometry, combinatorics, series, integrals, and more. Now more comprehensive than ever, Scalar, Vector, and Matrix Mathematics includes a detailed list of symbols, a summary of notation and conventions, an extensive bibliography and author index with page references, and an exhaustive subject index. Fully updated and expanded with new material on scalar and vector mathematics Covers the latest results in matrix theory Provides a list of symbols and a summary of conventions for easy and precise use Includes an extensive bibliography with back-referencing plus an author index Additional ISBNs0691176531, 9780691176536Scalar, Vector, and Matrix Mathematics: Theory, Facts, and Formulas – Revised and Expanded Edition is written by Dennis S. Bernstein and published by Princeton University Press. ISBNs for Scalar, Vector, and Matrix Mathematics are 9781400888252, 1400888255 and the print ISBNs are 9780691151205, 0691151202. Additional ISBNs include 0691176531, 9780691176536.
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