Incompetence at it's finest

I requested my fibre line be cancelled and a new one installed as I had moved to the next room. Just after the original fibre line was installed I moved. Openserve came out to relocate but advised to leave it next door which was okay with the tenant at the time. The tenant gave notice and I requested the cancellation and reinstallation. . This was supposed to take place beginning of March after numerous service requests and emails and weeks of frustration. I was contacted by Supersonic on the 30 March at 10 am. I was told my installation would take place around about the 12 April as there had been confusion about the ready installed fibre line and my relocation having the same address. He advised I change my address from unit I to cottage at the back he also told me that normally a clawback was payable of just over R 800 but seeing as I was taking a package slightly higher than the other one, no clawback would be invoiced. I then received an invoice for the clawback. I immediately contact Supersonic and gave them the time and date of that call. Till now that invoice has not been credited and my monthly payments have been unallocated and taken against that invoice. My account is now 3 months in arrears. I refuse to make the monthly payments until this is sorted out. I have emailed their complaints department and heard nothing. I have sent service request after request as phoning them proof useless as a recording cones on saying my account is overdue and the line disconnected. This shouldn't be this difficult to understand it resolve but 2 months later its proofing to be a nightmare and they are threatening to disconnect my line. Please can we resolve this . I've been a bookkeeper for more than 30 years I have never unallocated a previous invoice to pay an invoice done after the allocation especially when the client has that specific invoice under query