Horrible customer service and unnecesarily annoying calls

I am so annoyed, I do not understand why i get 3 - 4 phone calls a day on the same case, I had paid up the Tracker account that was handed over to credit solutions, yet I still get phone calls everyday about the payment that is outstanding, when I asked the guy who called me this morning he said their system automatically calls me because I owe them, when I do not even owe anything as I had settled the account on the 15th of February 2018, I this afternoon I got a call from someone by the name of Zanele, who said that I owe them, I just do not know how their system works, I am so tired of explaining the same thing, please sort out your housekeeping issues and leave me out of it, if they were asking for proof of payment I would understand but no they never ask for that instead they tell me the same story of their system that states that I have not paid them!