They are breaking the law and you can stop it. Obvioulsly you have not tried since they keep calling..
Go to www.ftc.gov to learn about your rights and how to deal with them
Don't waste your time talking to debt collectors on the phone....
Your first step should always be to request validation of the debt per your rights under the Fair Debt Collection Practices Act.
Send them a letter via Certified Mail + Return Receipt stating:
Per the Fair Debt Collection Practices Act, cease all verbal communications with me about this alleged debt
Per the Fair Debt Collection Practices Act, I am requesting written validation of this alleged deb, validation that it is within the statute of limitations and validation of the original "date of delinquency."
I will pursue FDCPA violations if your office continues to call....
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If this does not work:
Next time they call, read the following statement:
Pursuant to [your state] state law, this is to inform you that this phone call is being recorded. If you do not consent to being recorded, you need to terminate this call. Pursuant to [your state] state law, continuation of this phone call after officially being informed that it is being recorded implies consent to be recorded. This recording will be used to pursue Fair Debt Collection Practice Act violations in a court of law.