Bad service and Harrasment

I am getting collection calls from Credit worx for altec netstar . I had a tracker for the car about 5 years ago . The contract expired and i was refunded my money back that i was paying for the tracker that i didn't have as my car was sold .

I have send them several messages and they stopped contacting me now all of a sudden a get an sms and call from them .

Kindly refer this account to the tracker dept for write off