Three months of no salaries and no salaries of...

The Ministry of Human Resources and Emiratisation (MoHRE) issued Ministerial Decree No. 739 of 2016, which stipulates :that

If the salary has not been paid within 10 days of the due date registered in the WPS, it is considered “late.”

If the salary has not been paid within one month of the due date, the employer is deemed to be “refusing to pay wages.”

So all you have to do is to contact MoHRE by visiting their local labour office to get advice and support, then accomplish and submit an application form that you'll find in their offices,

You have to submit these documents with your complaint too:
 labour card, 
Emirates National ID, 
labour contract, 
and other documents maybe require, it may vary on a case-to-case,
Concerning the hold of the passports,

employers withholding the passports of its foreign employees is prohibited under Circular No. 267 of 2002 issued by the Ministry of Interior (MoI) - unless it is carried out by the judicial authorities in accordance with relevant provisions of the law.
If your employer refuses to return your passport, you may consider approaching the Ministry of Human Resources and Emiratisation. You may also file a complaint against your employer at a police station.

If, in the event that the question is intended otherwise, you can kindly ask it in detail and we will respond to it in the shortest time,