The contract is an important document and is totally different from the QID. A legalized contract makes it mandatory for both the employer and the employee to stick to the terms of the contract. It also makes it obligatory for the employer to pay End of Service benefits to the employee as per the laws of the country. By not giving a copy, the employer possibly has dirty intentions in mind. You can report the matter to the Human Rights Committee or the Labour Court and they will help you out. But keep mind by doing so, the employer may retaliate by sending you home after cancelling your visa which will act as a lesson to other employees in the company.