complain

I had a tracker with altech nesta that was handed over to credit works due to outstanding balance of which I settled on may and I cancel the tracker ,but credit work still calling me for huge balance that I dont know where is it coming from and altech still sending messages whe I call back to credit works they say I must go to altech and altech they send me to call another dept and they gave me invalid email address and all this time Iam using my airtime now my name is on arears need solution please