Exploitation of customers

I'm very disappointed for the terrible service I've received from Tracker Finance/customer care consultants. I called Tracker on the 19th of March 2020 informing them that I no longer have a vehicle and would like to cancel my contract. I was given an email to send an email to of which I did on the same day. I was well aware that if I cancel my contract early I'll be liable for certain amount for cancellation. I waited for months to hear from Tracker but no one contacted me on the cellphone number that I had given them. Fast forward I started receiving threatening emails from a law firm stating that my account has been handed over. I was shocked because as far as I know I had no installments behind as I had been paying monthly without fail prior to me selling the car. I called Tracker and spoke to a consultant who I don't remember his name I think it was L Leshabale who checked and confirmed that I indeed sent an email requesting a cancellation of contract. I waited for his call, and ended up sending him an email which he rep**** and stated that I had to pay for installments which I don't owe because I had sold the car and informed Tracker on time so that I can be penalised for cutting the contract early . I was told that they've been sending sms's to a number that I'm not even using anymore! I had included my new number on my email& was given an automated generate Tracker work number to acknowledge my email. Funny thing is that Tracker was sending me messages to an old number but when they handed me over, they gave legal firm a correct number, how convenient!.. So is it my fault that Tracker didn't call me as soon as they received the cancellation? So now I must pay for legal fees, installments for the car that I don't even have and for the cancellation? This is unfair, if this is not taken seriously I will be taking it up with the Ombudsman as Tracker's conduct is unfair and they're trying to exploit me.