central maine power co. ripoff

AS A CONSUMER, I gave dealt with CMP for many years and found them to be fair, until two years ago. Our power bills started to drop. We did not think much about it. One day, a CMP employee showed up to change our meter. this was after almost 18 mo. of lower bills. He said the meter was not working. The next month we recieved a bill for over 1000.00. their explanation was that it was our responsibility to report that we wrer getting lower bills and they were backcharging us for one full year of power they estimated we used. We went to the maine public utilities commission who upheld CMP's decision. please help. i have paid the bill down to about 500.00 but it does put financial pressure on the family. thank you.