Really depends on what their shipping/return policies are. Beyond that, they’re just doing customers a favor in the interest of maintaining good will; amazon customer service has clearly made it a priority to go above and beyond in many circumstances, but not every other retailer does.
Having said that, see part of monoprice’s return policy I pasted below. Since this is a defective item, the rep you spoke to may not have been entirely consistent with their stated policy (though it’s possible he was). Either way, good luck.
Returns of Products are subject to Monoprice.com’s current return policies which are set forth here on our website and on the invoice. These policies may be subject to additional or lesser return rights adopted by the manufacturer or publisher. The Terms of Sale represent the complete and final agreement between the customer and Monoprice.com for the matters set forth herein and shall be supplemented only by the prices, quantity, and descriptions set forth in Monoprice.com’s invoice for the relevant sale. Terms contained in customers’ purchase orders, offers to buy, terms and conditions, and the like shall have no effect.
For Refunds: All returns for refund must be authorized by Monoprice.com within 30 days of the delivery date. There is NO RESTOCKING FEE applied to any returned item(s). However, S&H cost is not refundable.
For any items being returned that are non-defective, we would not be able to cover the shipping charges. In order for you to return item(s), we recommend you use a cheaper shipping method such as USPS/UPS standard. Thanks for your support and we apologize for the inconvenience.
For Replacements: Replacements will be provided for any defective product within the specified warranty period for that product. Replacements will be the only recourse for returns after 30 days from the delivery date have passed. Monoprice.com will only replace item(s) for the exact same item(s) during its warranty period. Sorry, we cannot exchange one item with a different item. The Product ID (PID) must be the same.
Out of Stock or Discontinued Items: If you return a product for replacement and it is Out of Stock or Discontinued when the item is received, you may be contacted by the Monoprice.com Returns team and offered a suitable replacement or option for a store credit.
For Defective items: If the defect is reported within 30 days and a replacement is requested, we will send out a replacement immediately and cover the shipping of the replacement item. If return of the defective item is requested by Monoprice.com, you will be emailed a pre-paid UPS return shipping label to return the defective item to us. If no return is requested by Monoprice.com, you will be asked to discard the item.
If a refund is requested, Monoprice.com will issue a refund once the item is returned. If Monoprice.com requests for the item to be returned to us, we will email you a pre-paid UPS return shipping label to return the defective item. If no return is requested by Monoprice.com, a refund will be issued within 1-2 business days. We will issue a refund on shipping paid if, and only if, the defective item is the only item on the order. If there are other items that are being kept on the same order, no shipping refund will be issued. A partial shipping refund may be issued if the returned item is the bulk of the order. Partial shipping refunds will be issued at the sole discretion of the Monoprice.com Returns department.