I received a letter from AMCOL stating that I owed {$490.00} for a hospital visit on XX/XX/XXXX. I was not in the hospital on XX/XX/XXXX and I had not received any prior letters from the hospital stating that I owed money. I also did not receive any letters from my insurance company stating they would not provide coverage. I wrote a letter to them explaining this and asked for verification of debt. In return I received another letter and a bill which was dated for XX/XX/XXXX. There was no mention of the incorrect date on the original letter. The bill also shows that the total amount was covered by insurance and that I did not owe any money. I called AMCOL to have the account closed and they refused so I asked for verification of debt again. I faxed them the bill showing them that it does not show I owe any money and still continued to call me to collect debt.I asked again for proof of debt and received nothing. I also wrote them another letter and copied the bill I was given asking them again to close the account or provide proof of debt. I still have not received anything and the account is still open and effecting my credit score.