I have been making regular monthly payments on an account I co-signed for on behalf of my daughter for the past five years. Private loan was with XXXX even though I always made payments to AES. I was given an account number and have used this same account number to pay on this loan. In XXXX of 2015, there was a transition between XXXX and AES and AES took over the full servicing of these loans. I continued making monthly payments as usual. My daughter also had another student loan with a different co signer. When this transition took place in XXXX, the payments that I was making were being applied to her other account and a portion was being applied to the account I was paying on. However, it appeared neither XXXX of us was making the full payment on either loan. AES reported late/missed payments to the credit companies which has severely affected my credit and that of my daughter 's. I provided proof of payment to them on the loan I co-signed for and have been making regular payments on for several years. AES said they switched account numbers and I was using the wrong account number. I was never informed they changed my account number. My daughter was not informed either. They claim they can not fix this. I have my house up for sale and want to purchase another home and because of their administration of their handling of these loans, I may not be able to get a new home loan. The customer service staff at AES will not help and if you talk to a different person, each time you get a different story. They are affecting the lives of people and have been rude and do not seem to care about their mistake. Please help.