No accounting skills in Tshwane Municipality

In 2019 our old mechanical electricity meters were replaced by brand new electronic ones. Unfortunately they never corrected it on the account. From then on I only received estimated account readings. It was always on the high side. 1000+ units every month. In August 2020 I discovered the problem and started the process of correcting it. I complained online numerous times, went to service centres, numerous times with no luck. Eventually I ended up getting a councillor involved. After about 4 months they corrected the meter number on the account BUT they did not credit me for 24 months worth of overcharging. Since I started monitoring my usage, I only once used more than 700 units. Since Tshwane works on a sliding scale the difference is huge. There is no-one that I have encountered so far that actually understands the problem. Nobody knows how to fix it. They owe me thousands.