N power advice needed

The_main_man_2

Between Dec 2008 and Dec 2011 NPower supplied our business with Electricity based upon their own meter readings which they took at regular intervals. Upon business closing all our electric bills were paid up and nothing was owed. They took a meter reading, sent us a bill, we paid the bill by Direct Debit - simple.
In February 2013 NPower wrote to us saying that we had given them incorrect meter readings throughout the three years of our contract with them. As the result of this accusation, they had reopened our account, recalculated all our electric bills and demanded payment of over £30,000. Of course I demanded they tell me where I had given them incorrect readings when they had themselves read the meter on at least 9 separate occasions. They simply replied that all my readings had been wrongly taken and that, under the rules applicable to business, they were legally entitled to correct their mistakes and charge me for electricity used.
I took this complaint to the Ombudsman who decided that they were entitled to claim this money from me, despite the fact that Npower had ignored its own meter reading data and amended industry records showing our meter readings for the 3 years of our business contract. We are now having to pay a reduced bill of £13,500 to Npower.
In conclusion, Npower can ignore meter readings and alter industry records, send you bills and then cancel them later, then bully you by demanding you pay within a six month period under threat of Debt Collection Process. By ignoring their appalling behaviour, I think the Ombudsman demonstrated whose side he is on - certainly not the side of small business.
Npower will not admit any mistake it makes - whatever happened to "The Customer is always right"? It might be the law that they have to read your meter but is it against the law if they deliberately ignore the reading and bill you on something else?