Can they legally deny your EOSB for gross misconduct?
Yes.
These are quotations from Employee Regulations Manual:
Gross Misconduct is defined like this:
2.3.2 Gross Misconduct:
• Deliberately damaging or stealing company property.
• Committing any serious criminal offences at work.
• Committing proven criminal offences outside work that make the employee unsuitable to perform their duties.
• Deliberately endangering life or limb.
• Deception or fraud at work, for example, falsifying application form details, bonus sheets, expenses claims forms, personal records or sickness certification documents.
• Destruction, misuse, or improper disclosure of company documents, records or information.
• Discrimination or harassment of employees or a member of the public.
• Incapability on duty due to the effects of alcohol or non-prescribed drugs.
• Refusal to undergo an alcohol and/or drug test.
• Fighting or physical assault in uniform, or on company premises, or during working hours.
• Serious acts of insubordination.
• Action or conduct which could potentially damage the company’s reputation.
• Disregard of safety practices, procedures and rules.
• Disregard of medical advice.
• Unauthorised absence from duty for 7 consecutive days or 21 intermittent days in any one year.
Then you have this quotation:
4.5 Summary Dismissal
4.5.1 Instances of gross misconduct will warrant summary dismissal (without notice or payment in lieu of notice and, where permitted by law, without payment of end of service benefit or gratuity of any kind).
In my case I wasn't paid my EOSB because I went home without cancelling my visa. In my defence I have notified them that I went home because I didn't feel safe to give my passport to someone who threatened me with prison.
There is one more thing: since I've waited for my dismissal hearing for one month (hearing manager was on leave), I asked and I got one salary more. When I went to HQ to pick it up, officer at the counter read my HR profile (which was cancelled for me immidiately so I couldn't see what he saw on his computer) and told me that "they will not give me EOSB" and that he "doesn't know why". So I believe that they didn't have an intention to give me my EOSB anyway.
I don't think that I have violated any of these gross misconduct rules, but I guess they can interpret it the way they like it since they are not obliged to follow the rules of Dubai Labour Law and these are their internal Manual rules which they change often and without employees' consent, notyfing employees on these changes via emails.