Today i noticed the new V5 Mersenne site (could be possible that i'm pretty late

with this) so i followed the "Upgrade Instructions for Existing Users" and created a new account.
It seems i have chosen (without purpose) a login that previously existed from someone else and now i have his credits.

I only typed in the Login and a password on the "Register New Account" page. When I logged in to "my" new account there already were statistics for 3 computers and a link to his(?) V4 account.
What can i do to give his account back to him?