Scottish Hydro Electric Bill Help!!!

AliKate

I have been with Scottish hydro in my house for 8 Years when we moved in the house had a prepayment meter for electricity and out of laziness we never had it changed. We have just recently moved house and have received a bill for £900 for electricity on our old house. We always kept our meter topped up and never received any mail about electricity from them. I immediatly phoned them expecting them to just admit it was a mistake instead the person i spoke to was very rude and asked if we were struggling to make payments. ( we payed gas to them by direct debit with no problems) and also accused us of using a fraudulent card to top up the meter. They are refusing to speak to us about it now and say its being investigated its been 5 days and ive heard nothing. I dont know what to do and this is really worrying us. Has anyone had this happen to them?:(