This happened to me earlier roughly a few months ago. I log in to find that all of my games have been erased or some sort of weird rollback happened.
I had roughly 3800 games played, 12.5:1 win ratio and was rank 93 to find it all erased. Now i'm rank 15 with 110 games played. What gives? How the hell am i supposed to get this back?
The same thing happened to me today. I was at rank 79 and haven't played for a few days. Today I logged in to find I'm back to rank 59 with far fewer games played than I had. If this game wasn't so addictive I'd have ditched it long ago with all the bugs it has.