Claiming fees from ex-employer for extra work requested after leaving

Hi,

I used to work for a company under DMCC and my last day was on Dec 31, 2019. I signed my EOS one week before the said date as I had to leave the country.

Then they asked me to continue working with them till the end of Feb 2020 remotely from the USA as they didn't find a replacement for me and I agreed as a favour to help them (I have emails as proof).

When I asked them for a contract they told me it's fine we will continue with the same contract and pay you when your manager approves of your working hours and my manager approved all my work hours (I have emails as proof).

Now the company is experiencing a financial problem and didn't pay me the last one week of Dec 2019 + January and Feb 2020, they keep asking me to wait until they got some money and pay me.

Till now, I still have good relations with them, but the problem I feel the company will not recover as most of the employees including my manager filed cases and resigned because the company is not paying them.