I have every sympathy with the OP. PN have made a massive amount of billing hassle for themselves.
I've got the opposite problem. PN are applying far too much discount to my bills! I have no ultimate objection but it's bound to cause trouble one day. I have an open ticket for billing problems (they were previously overcharging and generally fouling up) but they don't seem to be able to give a coherent explanaiton of what's happening.
As for electricity and gas, I've been having a dispute with Tonik over incorrect billing. And they are meant to be one of the better energy companies. That one is close to going to the energy ombudsman though I think they have seen sense and will settle on something reasonable. I await their promised repayment.
Edited by ppppenguin99 (Mon 15-Apr-19 19:44:54)