3 months in advance is the legal limit, it's great. We also love our contract bindings for 2 years. Cunsumer friendliness here is heresy.
If you don't pay your electricity or water bill then that's a different story because utilities are not allowed to just stop service for things people's lives depend on. But utilities are more heavily regulated than normal subscriptions. For the most part, if a company tries to keep you from terminating a subscription and you say, "well, I'm not paying anymore. Do you still want to keep providing the service for free?" it's an effective way to get them to terminate service.
There are things called debt collection agencies. They are widely used by service providers.
Pretty dumb on their part if you ask me considering now I'm telling everyone not to use them because of their screwup and the fact that they would sell it to a collections agency over 1 months worth of payments.
Unless the company values their public image and return customers more than a small payment, which thankfully is the case for many. I just wouldn't count on it, ever.
I assure you that an insurance or telco will send unpaid bills to collection agencies. Especially if we are talking about one or two years of service.
Edit: obviously only if the company is geared that way. They could just end the subscription too, but wouldn't count on it.
It's a good thing actually, reverting a SEPA debit takes two clicks. But indeed, cancelling payments is definitely not a way to get out of a contract.