can an employer cancel a visa of the employee...

If you do not receive all of your entitlements to terminate the contract e.g. cash allowance for unpaid benefits, end of service benefits, unpaid salaries, repatriation expenses and airline tickets as stipulated for in the federal labor law.

You have to file a complaint against the employer at labor office

Support your complaint with proof documents on the validity of the complaint. Hence, to claim your entitlements after termination.

If there is any arbitrariness in termination, you have to claim compensation for this arbitrary termination.

 about that and ask for compensation. As the UAE Federal Law states:

Article 123

Where a worker is arbitrarily dismissed, the competent court may order the employer to pay him a compensation, to be assessed by the court with due regard to the nature of the work, the extent of damage sustained by the worker and his period of service, and after investigating the work circumstances, provided that such compensation shall in no case exceed the worker's wage for three months, calculated on the basis of his last wage.