Extremely high energy bills!

Dear Martin Lewis Forum,

I need some advice ASAP! I will be in contact with CAB soon but wanted to see if anyone has had similar issues.

I've lived in my single bed flat for three years as a student. The energy provider when I moved in was NPower, I wasn't aware that I could change and just continued paying £35 per month as the previous tenant probably did. I was quite naive when it came to energy bills and did not realise that this was a variable tariff that would change due to the providers estimates. I did give meter readings when I could but the costs were getting so high that my debit kept building up and eventually a monthly tariff of £92 infuriated me enough to switch, I was hit with a huge final bill from NPower, which I disputed, but due to my lack of knowledge and time, had to settle by paying £21 a month to pay off a £515 debt over 2 years. I simply accepted that the cost was high and I should've known to switch before.

Last July, I switched to SO Energy, thinking that this problem would be resolved by switching providers. I have been with them for a year and have been paying £28 per month as per their fixed rate package. I got a notification saying that my deal was about to end, so I looked elsewhere and tried to switch. I got a rejection, saying that I owe a huge amount on my electricity. I work 9-5 weekdays so I am never in, I didn't submit meter readings as previously this didn't seem to matter whenever I'd get monthly bills.

When I queried this, they asked me for a meter reading which I gave and I was told that I owed £1236!!! To make this worse, when I complained about it, SO told me that with the outstanding amount owed, my bills would now come to £180 per month, (out of contract tariff at the moment and they are trying to advise me to join new tariff 12 month contract) and that my monthly payments would actually be around £70-80 per month, and the extra £100 is the money I owe from the debt, based on my usage. 16525 Day, 24154 night july to august is my opening read on July 2018. Today I gave the agent rep my reading which was 24764 day 26502 night. I thought this annual energy usage was too high and maybe my meter was faulty or some appliance is faulty but even with that, the cost can't be £1236! The most recent bill for some reason covers 19-21 July only and doesn't spread out over the 12 month period. Other bills cover a month like they should but this bill states I used 3652kwh day 1543kwh night in 2 days! "Balance at your last statement £470.74, Balance brought forward £470.74, new charges included in this statement £765.36 amounting to my new account balance being £1236.10"

My question is: how is this possible??! Am I misreading something? I've paid £364 this year and can understand if it was underestimated and owe a bit more but £1200?! How can my annual usage be altogether £1500? Have SO calculated it wrong? Is someone stealing my electricity? This just seems incomprehensible. I have electricity only, I live in a bedsit by myself and I am being charged what I consider to be an extortionate amount compared to fellow flatmates. I am barely in during the day and my energy usage should be below average at most. Most importantly, what can I do? How can I escalate this and dispute this further? Should I call an engineer out?

If there's any info you feel I need to provide please let me know!