Npower

I'm sat here in total shock that an energy company can act in such a way. I'm so numb I can't think if to scream uncontrollably here or go to their office and scream outside of that. They sent me a letter a while ago telling me they might have got their meter reading wrong where they mixed day and night up, so I phoned the number on the letter to ask why that would have happened and the woman told me that it was just something they sometimes send out and to ignore it because it's doubtful they would have got the reading wrong. Then as a person who has one storage heater and a calor gas heater so that I don't have to spend too much in electricity, I had a bill for £900 pounds. I phoned the company in shock and the man on the phone told me to do a meter reading, then told me they had got it wrong so they would send me another bill with the correct reading. Instead of another bill, I had a letter from a debt collection agency threatening me with legal action if I didn't pay £900 plus extra for sending it to a debt collection ageny. I phoned the company back up and a woman told me there was no record that I had done the meter reading and to do it again, then told me it was wrong. I'm hoping they'll send me a proper bill as if not I'm going to have to sue them for mental distress. If it's so bad for me, then how would be be for an old person? I read another review site and everybody is saying similar things, so how do they get away with it?