Acting against immediate termination without a valid reason

Hi,

I have been working for a US company since Jan 1st, 2002. On Monday, 20th Jan 2020. I was given a letter of termination which only stated we are terminating your position.

I was on a UK contract from 2002 to December 2018 and they forced me to move to a local Dubai contract, I’ve been employed in Jebel Ali Free Zone for the whole duration.

I had no prior warning of this, but I was asked to leave immediately and hand in my company laptop and take a 30-day garden leave.

I was also given 60 additional days as an ex gratia payment. I have received the final settlement calculations which include gratuity.

My question is, is this the correct procedure that should be followed?

When are they entitled to cancel my visa? Is it after 30 days or after 90 days?

My visa expires on 20th Feb so it looks like this was planned.

However, am I entitled to ask them to renew my visa for the full 90 day period?

And when do they legally have to pay my end of service benefits?