Issuing an experience certificate while the visa was not issued by the current employer

I am a doctor in Dubai. I joined a clinic from April 2019 to date. When I joined the clinic in April 2019, my visa was not renewed with the new clinic because I had already a valid visa with another company and I was not able to cancel my visa as that company was sealed and closed.

The visa was changed only in January 2020 after the previous company cleared all their dues.

Now I asked my current employer to issue me an employment letter/experience certificate for my CV/profile update (On Dataflow). HR has issued me a letter with dates from January 2020 to date, but my actual experience is from April 2019 to today.

The employer says that this experience certificate can be used as a legal document to file a case against them that I worked without their visa from April 2019 to January 2020.

Can you please guide me if this experience letter (for the purpose of my CV and Dataflow) has any legal consequences?

And what can we do in this situation?

I will greatly appreciate it.

Thank you!