Well, I asked Sky to reduce my contract, and they did, dropped £9 a month from my broadband. Had to sign up for another 18 months, but £21 for 70Mb internet isn't bad at all on the grand scheme of things.
I cancelled a second phone contract I had for work - £18 a month, they offered to drop it to £15. I didn't need that in all honesty so I went ahead and cancelled it.
If you've signed up for something, that's the price you are going to pay. Don't expect companies to automatically give you freebies, but if you don't ask, you don't get, either.