Worst utilities supplier I've ever dealt with

Npower were my supplier at my last address and quoted me £120 per month for both my gas and electric supply.
I paid the amount I was quoted but received no bill for twelve months due to their systems being down.
Finally receiving a bill twelve months later I was devastated to realise that they had billed me an extra £1300 on top of what they had quoted me.
With a high usage of gas and electricity due to a severely disabled daughter I knew I would struggle to meet payments,which I did.
Last year I had to move from that home to another,I informed Npower of my change of address but heard nothing until one month ago when I received a court enforcement notice saying bailiffs where coming to my home for the total amount of £2900.
I immediately rang and tried to resolve the matter but with no luck.
They have ignored my calls to look into the late billing and have now said I have to pay their solicitors fees or face bailiffs coming to my home which I am petrified of because of my daughter.
So I have agreed to pay whatever they want me to pay because I fear they will come to my door.
All this was taken to court without my knowledge ,the case was heard without my knowledge and I have no court papers at all because the paperwork went to my old address.
I have been hounded by phone calls and their solicitors and have been shown no help what so ever. I have had sleepless nights for four weeks and feel physically sick.
I would never ever recommend this company to anyone and if I could give a minus star review I would.
Absolute torture.