Npower and still no bill

Alligg

I posted recently about moving to a new build house in Sept and trying to get a final bill from Npower so we can move utility provider. They are really taking the p*** now, how can a company that big not be able to get a final bill sent out? It would be different if I wanted to join them then they would be all over me like a rash. We have since put in a complaint after posting on Twitter(oh they were quick to answer me then) and when someone called us were told it would be looked at asap and could we give them the full details which we did the same day,now they have got us off Twitter we have received a letter telling us that it will be up to 28 days to be looked at!!!!!!!!! And then we had a message saying it has been passed to ANOTHER team and will be 28 days from their receipt of the complaint.
What a joke and what disgusting customer service
I JUST WANT TO PAY MY FINAL BILL we have been putting what we think should be enough aside each month but we cannot move to a new provider and save money and we dare not spend any money on anything else in case the bill is more.
This is making me ill worrying,is there anything else I can do?