Working in Oman without working visa - any consequences?

Hi

I accepted a great-sounding job offer in Oman some years ago. The employer made me work during 8 month period with a multiple-entry visa -they never applied for a working visa for me and some of my expat colleagues.

As a consequence, I decided to leave the company as it was very difficult to live in Oman long-term  without proper permits. I was never able to open a bank account or buy a car. The salary was paid in cash. My family also had to stay in Oman with tourist visas.

The family benefits mentioned in my work contract were never paid. For instance, in the beginning of holidays, we didn't receive any travel reimbursement to our home country, as was promised in the contract. Also, my salary was never paid correctly. When I tried to clear the situation and insisted the employer to get me working visa they had promised, they came up with different excuses and finally threads.

They did pay me settlement money in the beginning when I started working for them, as it was mentioned in the contract, but after that, the benefits mentioned in the contract didn't seem to have any value for them at all.

I was very stressed and finally I resigned and left the country with my family. I never returned my employer the settlement payment I had received, value of maybe 1500 usd, as I also did not receive a working visa or any other benefits they had promised to pay upon sining the contract. 

As you can understand, it was a scary and unfair situation for me and my family.

Because of my current (and amazing) work I have to travel sometime in the future to other gulf countries for business and perhaps in the future to Oman, too.

My question and concern is, could I be banned for entry to Oman or other Gulf countries if the former employer has reported somewhere that I didn't pay the settlement money ? There was no official proof as it was paid in cash and I had no bank account in Oman nor work permit. Or I I was granted a visa, could I face any problems entering other gulf countries because of this unfair situation?

I much appreciate your help!