I bought the wrong size on a mattress topper. Date was 12/21/18. I was going to bring it in to exchange a twin for queen. Due to a funeral. I cant return it for 2 more weeks. I have the receipt. Is this a problem?

I don't think you will have a problem, as long as it wasn't open? Not really sure, give it a shotm

Call the Walmart that you purchased the item from & explain situation: wrong size & date you will be able to return it. You can also; I think can start a return online as long as you have the receipt, which you do. Good luck.

They give you 30 days for returns

Should not be a problem if you have the receipt.