I had the same thing with Plaync, I wanted to switch my e-mail address, but I forgot my Plaync login AND pass. So I follow their FAQ and it said I had to mail them about it. They'd take a look and it'd be all solved in a few days.
I wrote that mail about 2 months ago.
I suggest you just e-mail them, tell the whole thing, don't worry, you're not the first one with this problem.

They'll ask you to fill in some questions about your account to proof you legally bought the game and shit, I can't really remember.
If you can't find the form I'll look it up for you.
Good luck!