Feel like scammed by a Chai chain

Hi Grapevine people,

Need suggestions and a little help on what I should do

So here's the context, I was working with a popular QSR Chai Chain which obviously doesn't sell Sutta or is a Bar

I resigned from there in dec so they held my dec salary for f&f, in my last week I got diagnosed with Typhoid and Jaundice both so couldn't attend last week and left for home.

Now they changed my last date to when I was in office even though from last 7 days I was not in office 2 were holidays and rest I contributed in 3 days through WhatsApp communication

After this they're holding my El encashment which was of 16 days saying they've cash crunch and have held for everyone but this decision was made almost 20 days after I left and they simply said we're not paying this to you

I'd ex-gratia/bonus in my CTC which had to be paid after I complete my 6 months but they denied that too

So the total f&f they've proposed is almost 50% of what was expected.

What can I do in this situation and what should I do?