<prompt> Human: Im actually posting this on behalf of my girlfriend, that lives in Mexico but is a US citizen. The following is what she wanted me to post verbatim.Today my aunt handed me a letter stating that I had been placed with a collection agency about a debt that I know I paid I also have the receipt. But the thing is my aunt didnt bother to give the letter until 2 months after it was sent and I dont have a chance at clearing my bad credit score now. Any suggestions as to what I should do next? Im 19 and this new to me.Just a little more background info on her situation, because she lives in a border town, she has her PO BOX in the states with her Aunt. The fee was for a tuberculosis test she had to take for her Child Development class and she DID pay the fee and as she mentioned has a receipt. Ive only been a lurker around here and already told her to contact whoever administered the test and the collection agency. Im not sure if that will do anything though, so any help is very appreciated!!  <response>: If its really only 2 months old - its not a real collection. Many of the major medical labs have their own collections departments that send out these letters. 