Have you actually tried this? Because having not tried it myself, I'd bet a paycheck that you get sent to collections, get a ding on your credit report, and you're still on the hook for taking it to court if you want it resolve to your favor. (Assuming U. S.) And as a cherry on top of that shit sundae, it's probably in the contract that you have to go through arbitration anyway.

When collections calls, you explain them the situation (service not provided or whatever, and evidence of trying to resolve it with them in good faith) and they go away.

Have yet to see a court summons or anything, although I'd love to see them try their lies in court.

I did not care about the credit report impact - it's probably the only valid reason not to do this if this is something you care about.

Thanks for the follow-up. I suspect UK does make a difference, but IANAL in either country. I do, however, have a bit of personal experience in the U. S. :-)

If you are relying on them for something other than the thing you don’t want to pay for, this becomes a problem.

For example, I disputed a charge with my CC from the Apple App Store when I was charged for an app that I shouldn’t have been years ago. They immediately cut off my access to the Store. Other apps couldn’t update, OS couldn’t update, couldn’t get new apps, etc.

But the fact that I have a billing dispute with a company and they are able to hold everything else that bit of technology touches hostage is just wrong. Imagine if you had a billing dispute with the city water company and they cut your city power because of it.