We understand that different players in the same household may play Marvel Puzzle Quest on Steam. We recommend if you choose to play Marvel Puzzle Quest on the same computer, is to please use a separate Windows logins and separate Steam logins, and log in to their Windows account before running the game on Steam.
If you are currently experiencing this problem, please try the following:
1) If there is a file here, delete it: C:\Users\<your Windowsloginname>\AppData\Local\Demiurge Studios\Marvel Puzzle Quest\slot0
2) Making sure Steam is running, launch MPQ. If you see the correct data, you're done!
3) If the incorrect data is still showing, check the C:\Users location again to see if a new save file was made. If so, there is something wrong with the connection to the Steam cloud game server.
4) If there is no file in C:\Users, then the incorrect data has overwritten the correct data in the Steam cloud save.
Please message customer support if you still need further assistance after this instruction.