I'm with EDF for gas and electricity. Just before Christmas time, I asked them to reduce my monthly direct debit, as I was in credit by quite some way and it was an ideal time to save some money.
Tonight I thought I'd do some meter readings, just to check that everything was balancing out ok. For the first time ever, I'm in debit ... by nearly £500! 
My current tariff is variable (I've only ever had fixed, but this wasn't an option at my most recent renewal time), but they have sent me an offer for a fixed tariff. Should I go for this instead?
I'm really worried. I've never owed them this much money before. For reference, I live in a Georgian 3 bed basement flat. Massive old radiators, mostly single glazing, newish boiler. My gas bill in particular is through the roof.
Thanks for reading 