unpaid bill

I have an outstanding balance of over $2000 from 2009 from when i was studying in the US. It tried to pay online but i forgot my user and password. I still would like to pay them back, but i dont know how to reach them or whom to contact. Plus my account was closed because i called after a few months and i found out that it has been reissued to another person and he is using my number.

I am outside of the US and will not be coming back, but i would like to pay this bill to settle my debt.

Whom do i contact regarding this issue.

regards,