French energy supplier wants 5,000 euros extra from me??

A French energy supplier wants an extra 5,000 euros from me for my gas after me paying 46 euros a month standing order. They say it goes back 2 years but its still a  ridiculous amount.  I lived on my own, was not there permanently so the heating was used less than 5 months per year. They kept me on the phone from the UK for over an hour and a half and said they would not put anything in writing before I agreed to pay the 5,000 euros. Anyone know what I can do about this. I will pay what ever I owe them but it cannot be this much, they also lied saying the 46 euros a month was for the electricity which again is ridiculous, thanks

You should tell us the name of the company and notify the local authorities. What do you need in writing? What can they do to you in the UK? I cannot understand this story. It was for how long a period of time?

My suggestions from experience:
Don't pay
Publish the name of the company
Ask them for evidence that you have paid less than you should before making an offer.
We have had constant battles with EDF who can't get their systems to work properly and regularly overcharge. Part of the problem is the French system of taxing taxes which makes the calculation more difficult. When you analyse an electricity bill you can see that the cost of electricity consumed is a minor part of the total.
Good luck

Those EDF bills are something else - all those taxes and extra charges...5000 is enormous, you have not replied to us, the name of the company, the period of time, the justification for the claim. Electricity is expensive in France, one must be careful.