Problem with renewal

Hi, I've called a few times about an issue with my renewal. I renewed my contract at the beginning of January for £82 per month and the renewal never activated so my bill has been coming through at £181 instead.

I called to get this dealt with, I was provided with a rebuilt package and ensured that these charges would be refunded and my bill would be brought back down to the amount that I signed on for.

However I just received a bill for £523.27

I was on the phone to customer services for nearly 2 hours, I got passed around 5 different people and I still have no solution. I was also given a phone number without a prefix so not even a phone number.

What can I do?