May I ask if its possible to the employer to...

If your inquiry is about the employer terminating the work contract and canceling the visa without the informing the worker, find the following information:
It is among the documents that must be presented when submitting a visa cancellation request is the document signed by the worker and by which proves that he has obtained all his / her financial rights.
If the employer canceled the visa arbitrarily without notifying the worker, the worker can go to the General Administration of Residence to ensure that his / her signature is not forged on this document.