T-Mobile / Superior Asset Managment CREDIT REPORT DAMAGE CLEARWATER, Florida

A few years ago I moved to California for a job and I went to T-Mobile for a personal cell phone.  After almost year of working the company I was with layed me off.  I had trouble paying my bills and my T-Mobile bill became delinquent.  Once I got back on my feet I paid the collections agency that T-Mobile gave my account to, Superior Assets Management and from that point forward my debt was cleared on this account.  It has been two years since I cleared this debt and I am now trying to buy my first home with my new husband and our loan officer informed us last week, much to my surprise that I had an account in collections.  And to my further surprise it was for the T-Mobile account and Superior Assets Management is reporting it as Unpaid / Collections.  I have been trying to get in touch with ANYONE at Superior Assets Management with absolutely no luck.  I need to get a letter from them stating that this debt is not owed so that I don't jeopordize getting my home.  If anyone has any contacts for this company I would greatly appreciate it, I need this letter immediately.