Poor service and dishonesty

I have a installed a sub meter for my tenant so that he will be able to manage his own electricity but whatever amount that my tenant use I as the landlord I am supposed to get it back but this company somehow take at least R300 from that amount. Their reason is that the shop take a percentage and them as well take something which I think it’s really absurd, not mentioning that they stutter when I ask what is the charge per unit. I’ve been complaining for way too long and I’m getting tired of their poor service. Few months back I asked them to change my banking details and till now I’ve never received the money that was bouncing back from my old account.