hi,
if it is a devil company:
not the first time I hear of such practices, and I bet they will fire you 1 month before the contract expires and you will get calls from their attorney asking you how you are going to pay them back.
bonding is ILLEGAL in europe, and I don't think they have something to win in this mindgame.
if it's a good company, ask them to review the contract.If they say no, it is a devil company.
you can not sue an employee because he has been fired for no good reason.Just get a good juridic protection.