Hi guys, I'm new here.

I read through some of the stickies and they are defintely valuable. But I am kind of lost on what kind of direction I should take regarding my recent credit blemish...
I recently received a letter from a collections agency about a 90$ debt I owe.

The original creditor is AT&T with whom I currently have an active account in good standing. So I called AT&T and found out that I had unpaid bills from my last account with them. This is what happened:
- About a year ago I closed my cellular account with AT&T to open a new family account with them. My phone # was changed but I stayed with AT&T...
- I moved to a new apartment shortly after the account cancellation/activation.
- AT&T told me they mailed notices to my old address and never heard back so they sold my account to a collections agency.
I find it very odd that that they sent my old account to the collections although I do still have an active account with them. I feel they did not put in reasonable efforts to contact me. They obviously had all my updated contact information in their system because I had another active account with them. But they never bothered to check and find the link...
Now my credit report shows a collections account and my score is not good... How should I go about reparing this? Is this something I can open an dispute with Experian? AT&T didn't sound like they were willing to settle this with me directly.....
