just stress them and remember them that the contract is two sided. If they don't fullfill their part, you can terminate the contract at any time
It's not hard to fullfill "UP TO 8 mbit". All they are guaranteeing there is that you won't be seeing anything over 8 mbit... Even delivering dialup speeds technically meets that.
Keep in mind: these companies wrote their contracts, and I'm sure that they picked their words very carefully.