I sent a validation letter to Gulfstate credit, return receipt, certified, etc. I sent to: PO Box 105460 2960 NW 14th St. Miami, FL 33125-2010. This was the address listed on my Experian report.... does anyone else have another address? This is a $12 collection! I called Experian today and asked how they verified the information (re: Gulfstate), was told that it was by mail, or electronic transmission. I asked if my verification was by mail or electronic and the RUDE rep. said she could not tell me. I asked again, she did not acknowledge my question, so I asked once more. Can I just say what a bee-ya-tch!!!