Pudge is right, you need to send a C&D. Follow the steps in what you need to know:

http://800notes.com/arts/Jb8EW-eDhQA/harassin ... ou-need-to-know
See Residents post here also:
http://800notes.com/forum/ta-34af6a034ba34b6/unending-collection-calls
Templates of Letters:
http://800notes.com/Phone.aspx/1-319-242-7350

http://www.ftc.gov/os/statutes/fdcpajump.shtm
http://www.consumerfinance.gov/askcfpb/search ...
http://www.consumer.ftc.gov/articles/pdf-0096-fair-credit-reporting-act.pdf
http://www.consumer.ftc.gov/articles/0149-debt-collection

To File complaints FDCPA/TCPA violations:
Your State Attorney General
Their State Attorney general
www.naag.org (you can find your state AG at this link).
https://www.ftccomplaintassistant.gov/#&panel1-1
http://www.consumerfinance.gov/complaint/
http://www.rcfp.org/reporters-recording-guide/state-state-guide