Don’t use them!! They keep asking for more money!

I paid my outstanding amount (which was not covered by my medical aid) on the 20th of October already via public recipient on my online banking. I got an sms on the 1st of November to say I still owe that amount. I immediately emailed with my POP and said you need to update your records. Till today (4 working days later) I have not received a reply. This morning, I receive another sms stating the amount is still due and I will be handed over in 7 days. EXCUSE ME?!?!?!?!?!?!? Are you going to pay for the damage against my credit record?! So I emailed again but obviously I will get no reply so how the **** do I get rid of you??? I will be sure to tell every single doctor I go to, to NOT MAKE USE OF YOU because if this. I often need to go for blood tests and your stupidity just caused you a bit more money. Sort your **** out!