If I finish my contract without having my vacation...

We would like to inform you that according to the UAE Domestic Law
Article (23)
1. Either party to the contract of employment may dissolve it by unilateral will if the other party breaches its obligations under Articles 15 and 16 of this Law.
2. The employer and the worker have the right to terminate the contract. If the contract is terminated by the employer, and because the worker does not return to the worker, the employer will be obliged to provide a ticket for the return of the worker to his country in addition to payment of compensation equal to the comprehensive wage for one month and any other entitlements to the worker in the employer's custody, Other damages may be adjudicated by the Court.
3. If the termination of the contract by the worker and due to him after the period of experience bear the expenses of returning home, in addition to payment of compensation to the employer equivalent to comprehensive pay for one month and any other entitlements to the employer in respect of the worker and any other compensation may be ruled by the court.
4. In all cases of termination of the employment relationship, the Ministry shall have the power to grant the worker a new work permit or not to grant it in accordance with the rules determined in this regard, and taking into account the provisions in force in the State.
Note that the employer doesn’t have the right to take your passport, so you can ask for the passport, if he refused then you can file a complaint in the police office and take a copy of the complaint to the labor office to prove the violation. As the law allows the governmental departments to take the passport otherwise it is violation.