Listing Question

Good evening all. I’m a newer seller and have a question regarding a listing that contains incorrect information. I have been doing R/A and wanted to list a shirt I purchased from a particular manufacturer however, the upc pulls up the wrong size on Amazon. It’s the same design, just a size smaller. (I totally missed this in the store BTW). Anyway, my question is, is there a way to rectify this? I’m pretty sure the size is just incorrect on the listing, since under variations there are two for the same size with different upc codes. I looked through the variations and didn’t see one for my size with a different (aka incorrect) UPC. The store I purchased from doesn’t allow returns, hoping to be able to list the item without worrying about it being returned. TIA