Here in Belgium a registered snail mail is sufficient in general to cancel a service (i.e. cable).
Last time I changed internet provider I waited the expiration of the contract, but I think now they have more consumer friendly laws and you can change with much more ease.
The general idea is to foster competition between companies making it easier for a customer jumping ship and woting with his wallet/her purse.
Of course other governamental intervention (forcing the old telecom monopoly to lease their infrastructure at reasonable price and now trying to do the same for cable) is a godsent.
You can always argue that the incumbent has the advantage (because you may want to avoid the ping pong between the virtual operator and the incumbent), but sure as hell it looks infinitely better of what people have suffering in USA.
I got friends going to work there and being flabbergasted by the internet connections and prices...