I do not understand why they charge 50.31 per ch...

I do not understand why they charge 50.31 per change of payer .... they take money from everywhere. I have started living in a rental house and I have been charged for change of address, and a friend who has bought a house has also been charged. That is to say: I am charged for being a tenant, and my friend for being the owner ... I do not understand what scheme they follow. Anyway ....