Oh, I can relate to that! I have a "ding" on my credit report for an alleged unpaid cable bill that arose because a defective cable modem was replaced by a technician, but the new serial number not recorded. So when I returned the modem we had and got a receipt it did not match the serial number in the system, so a $300 invoice was generated. Even though the cable company told me to ignore the invoice, it still got reported to the credit bureaus as delinquent and haunted me for 7 years.

You can legitimately get your credit report for free from all three agencies via annualcreditreport.com.