What happens if severance pay is offered over a period of 6 months but i have to leave the country because I have an L1-A? Can I get some tax relief since I cannot take use social security or Medicare benefits? Or is there no way out of it? It’s not an

Hi. I’m stuck in my home country due to covid-19 following 3 months of unpaid medical LOA. Since then have been offered an exit severance which will be paid out over a period of time.
What are my rights/negotiation options considering my visa status which demands I cannot return to or stay on in the USA (if I did return)? Do I need to pay social security and Medicare tax along with federal and state tax? I can’t avail of the first two at all so is there some way to make that money back? Is there a way to ask for a lumpsum esp because I have my stuff in storage and other outgoings to take care of? Please advise.