I have a medical debt collector contacting me about a medical invoice I have no knowledge of. It is not a huge amount, about $650 and it appears to be a claim that is approximately 3 years old. I am in the process of applying for mortgages now and I would just assume pay them off to make it go away but I have the following concern - it does not appear the amount had been reported to the credit bureaus and I have heard that paying such an amount is essentially an admission of guilt and that it can be reported as a late payment. I have disputed the debt with the agency for now to buy some time as I research the correct course of action. I am not a fan of paying something I don't owe but my primary concern at this time is protecting my 800 credit score. What is the best way to protect myself and the best overall course of action?