supplier has been undercharging now wants it all back

edgibs

Hi,
my supplier has been working out my gas bill in M3 metric cubed formula. They have now asked me to check my meter and it says on it FT3 which means feet cubed. This will roughly translate as an extra charge of whatever my gas bill is times 2.83. It works out over the two years I've been with them as about 500-600 quid.

So my questions are,
1.I know I used the gas but it was their mistake as I had no knowledge of underpaying, so are they culpable in any way?
2. can I insist on paying them back in instalments with no interest being charged.

Any help would be greatly appreciated.

david39

I think that you certainly are due to pay them money for part of the undercharge.
I believe that they can only demand back the undercharge for the past twelve months.
Under the circumstances, you are entitled to ask for time to pay and they should be amenable to such a request.