Can a person be reinstated when he was terminated after signing LOA

Sir, I was appointed by a UAE company and has signed a letter of appointment. The company has proceeded with entry permit and air ticket for travel. Later, I had requested them for clarity on passport holding in Sharjah as I have heard that employers hold the passport at their will and do not let the holder keep it restricting their will. Once I asked for clarity and reconsideration on wages - they said we are termination your appointment and asked for a claim for visa and air ticket expenses. Here the point of contention was clarity on passport holding in Sharjah and whether reconsideration can be given on offered salary. The company itself said that they no longer want to hire me and claim the cost and if not given- legal course would be taken.