Specifically with respect to Tony T1's link... note that you have 14 days to to get the return authorization. You then have 15 days to actually make the return. So, if you are close to or at the 14 day point, you still have plenty of time to make the return so long as you get the RMA number right away. You might also want to give MacMall a call and see if they'll have some flexibility as you're looking to make a new purchase as well.
HOW TO RETURN PRODUCTS: Please contact MacMall within 14 days of shipment for a Return Authorization (RA) number before returning your product to MacMall. No returns of any type will be accepted without a RA number. For faster service, please have the following information on hand when calling for an RA number: customer name, order number, item number and serial number and the reason for the return. Once an item arrives at MacMall, we will immediately send a replacement or issue a refund. Returns must be made within 15 days of Return Authorization being provided.