EZY are a big company with ample legal resources - they can look after themselves. If they want to get out of the contract and think they have a case to argue, they will be able to put up a fight unaided. If they want to lobby the CAA / Dept of Transport / Dept of Trade + Industry / other regulatory bodies, I'm sure they have the ability to do so.
If the contract is unfair - then they can go to court and get the lawyers involved. If the contract is fair - then it's up to EZY to find a way to resolve it.
Alternatively - it may be that EZY have decided that their corporate resources are best utilised in other parts of Europe - such as France and Italy and that Manchester can take a back seat for the time being.