Mobility

I have been in bahrain from 15  june 2012. Last month I have received a new job offer from Bahraian itself. So I apply for mobility on january 26 -2014 and same day I sent my resignation letter through registered post.
I am working with this companey in contract base. That is they provide the visa and they placed me in ministry. Intailay my contarct is for two years, But thay didnt metioned anything about my resignation formality on my  job contract letter ( simply as per bahraini labour law).As per back ground history of my compney, if sombody resigned from the companey they sent lawyer notice to the employee metioning that "we are rejecting your resignation.Because of your resignation I lost 4000 dinar, you pay this amount and lave this compney. " Is such kind of letter is legal.?
can my current employer can refuse my mobility application?  If they refuse what i can do?  If they send such kind of lawyer notice what i want to do?

I think you may have your dates wrong. Please correct your original post

Well, it sounds a bit dodgy to be honest. If your dates are correct, then you will have completed your initial probation period and they shouldn't charge you for your relocation fees. Had you resigned during your probation, it would have been a different story.

For mobility, the company should not be able to block it, however they can still cause trouble if they have the legal grounds for you owing them 4,000 BD according to them.

I would go to LMRA and explain the situation. They are helpful. Take a copy of your contract.