Lawyers with no proper system or communication

I was handed over by our vet to this legal company who collected. I have been paying as regularly as possible. When I wanted to settle I was told I would be penalized. I reported them and they reversed this statement. I was presented with a statement. I mailed them to say I will settle as soon as the funds arrive, which I duly did. I believe my intention to pay was clear, I also let them know if I would be late. They never provided me with any updated statement. The next thing I was told I am blacklisted - unfairly and without my knowledge or right to dispute after settling. I then was invoiced for all sorts of things including letting them know I will be settling. How can one be blacklisted when settling according to last communication, and have shown that I had all the intention to settle a R30,000.00 bill. The lawyers in this country are ******** on how they conduct themselves.