Depending on the details and how this went down, the SOL may apply. All of this depends on the accuracy of that credit report.
OP- do you have a record of when you made your last 6 payments? Also, there are other defenses as well. If the Plaintiff bought the debt from the original creditor, the collector cannot swear to the veracity of the records of the creditor due to the hearsay rule. That means that they need to produce either the creditor's record keeper or an affidavit from the creditor that swears to the accuracy of the records.

