Cant Downgrade, cancel or do anything

I've been with Virgin Media for many years now, but for the last 2-3 years or so I've had some financial difficulties and have requested MANY times for virgin media to downgrade my services so that I can continue paying for it without any issues, but they somehow get away with increasing the amount of stuff I get and ultimately having to pay the same amount making it out like 'I'm saving so much with these added discounts', I've been paying almost £100 a month for a while now for services I hardly use at all (I only use the internet, something I tell them every single time), I've tried removing the phone and TV packages MULTIPLE times and they make it out like its some impossible task, how crazy is it to just want to pay for internet?

I cant even leave because of the insane cancellation fee. I didn't leave before because there was no other high speed ISP in my area at the time, and also getting stuck in new 18 month contracts every time I try to reduce my package which usually amounts to maybe £10-15 less only for it to increase again in April or whatever the usual date is. 

There's even been times when they've broken their word promising IN WRITING that there wouldn't be any price increases only for there to be a price increase 2 months later, and when I complained about it WITH EVIDENCE, no one did anything at all, and it eventually got stuck in an automated email loop not going anywhere. 

I'm at my whit's end with virgin and they cant convince me they can resolve anything at all (Because they haven't), I've spent years paying a fortune on a service I hardly use, they haven't done a thing I've actually asked for, I can barely make my monthly payments and I cant afford to pay the cancellation fees. I don't have it in me to speak to them anymore, everyone I speak to seems to have their own solution EXCEPT the one I ask for, is it really THAT hard to just pay for internet.