Bad customer service from MTN call center agents (contract department)

I am not happy with the customer service from MTN call center agents (contract department). I have been trying to settle my account that I stopped paying when I was retrenched during early days of COVID-19, but instead of been assisted, every time I call they keep telling me to call after 3 days. For 3 weeks now I have been calling MTN every 3rd day with no assistance. Why? Why cant they do their job. Some of them are even so impatient as if you disturbed them by calling MTN. Why do I have to beg MTN agents for assistance as if they are paying me and not the other way around. I don't even use the phone and the sim card was blocked 2 years ago, but all I get is a stinking attitude from MTN agents. After this, I am never buying from MTN. Bad customer service...