question what can i do?

It doesn't matter if you have your receipt- they gave you the wrong shoe!!! Go back to the store, tell them you lost the receipt but they gave you mis matching shoes- they should give you the right one with no problem, especially since its their job to make sure your shoes match before you leave the store

The store made the mistake, not you. So receipt or no receipt it would be worth the effort the go back and explain their mistake. They should be willing to right their wrong, but you might think twice on your future receipts when buying stuff. Our mistakes our our lessons to learn from! Good Luck!

First off...why didn't you try both at the store? 2nd, why didn't you get a receipt? I not sure how to stretch the left boot, but you can go to a shoe store and buy those inserts to try to keep them stretched, but I doubt it'll do much to make them comfortable.

You should take them back and the correct size they should have a exchange policy w/o a receipt.

You could look up the company on the internet and email them.

Go back to the store, they should have checked them even if you didn't.