Poor service, and incorrect readings

I have been experiencing issues with this company I live alone, and they insist that they do not estimate electricity usage. However, it does matter whether there is load shedding or not. My meter bill is very expensive, and they blame winter, etc. I have been dealing with this problem for years now, and when I call, I feel disempowered by them. They say electricity tariffs are high and give me excuses. I have requested a proper investigation of my meter to see if it has been tampered with because none of this makes sense. Recently, they informed me that they would charge me R950 for the investigation. This seems completely unfair, and it appears to be a tactic to discourage customers from pursuing their concerns further. I am appalled by how they treat people. I am already struggling with their high readings and now they want me to pay an additional fee to check their readings, which they claim are not estimates. I feel as though I am being taken advantage of. This situation occurs every year, and I want to know who else is using my electricity.