I just bought a snail from a big company pet store which I've had issues with in the past but they are the closest place to get snails. I bought a blue mystery snail to help with algae on the glass in my tank. The last snail got was a while ago and had the same problem. I put him in the tank and made sure he was faced down so he could crawl away when he decided he wanted to. Just checked on him and he was flipped back upside down from the current maybe? But his underside is like a disk and looks hard like he dried out. I'll try to get a picture and figure out how to post it if that will help