Eskom estimate 10x more than actual reading

Hi. Acc nr ***. I use +-70 units every month. 10kw solar system with Eskom as backup. Every month i send in my reading, which should result in a R650 bill. Evey month Eskom decides to use their own estimate and send me a R5000 bill. So for the last 2 months my acc is R10 000.00, whilst it should only be R1200. Every time i must wait for an actual from Eskom and then my bill is 10x less than their estimates. This month Eskom cut my power because i dont pay R10 000 whilst a actual wil show only a bill off R1200 for the same period. Phoning the call centre is useless, i tend to get the *********** agent