Incorrectly billed & inability to resolve! BAD SERVICE

I've been a client of WebAfrica for a number of years. Moving house recently, they imposed a R3000 bill on my account, saying it was for a full installation at my previous residence. When moving into my previous residence, there was an existing fiber installation, so no install needed. Moving within 12 months of, there is an apparent charge if there was an install. The evidence has been supp**** to them that there was an existing installation at the previous residence but it has taken them in excess of 3 weeks to resolve this matter. I refuse to pay for an instal that did not take place. My services, which was moved to my new property & upgraded, has now been suspended. I've been on their WhatsApp message "service" for days on end, dealing with Sisanda N, Jeandre De & Nqobile D... All without resolution. Being transferred from department to department. Nobody taking ownership of the matter and resolving it. It has now been escalated to some supporting team but hours and hours later, still no feedback. This is preventing me from earning an income due to their misconduct, not acceptable.