You have nothing to fear from bailifs, as said you would have to lose a cout case first. If it does go to court you would have plenty of warning, and frankly, the case would be thrown out before it even got to the hearing stage.
If I were in your position I would switch suppliers, they are in clear breach of contract and so cannot hold you to the 12month term. Then let them Chase you for whatever you owe. I certainly would be in no rush to tidy up after their mistakes.
As for threats of legal action from debt agencies, simply bin them. Nothing will come if it, and its pointless entering into communications with them.