Salary not given

Actually I have served notice period in my previous company on 23rd December and mentioned that I would work upto 30th January but due to my illness I was not able to work after 26th January I had been detected with jaundice so it was not possible for me to work in that condition but because of that they are not giving me the last month salary and my previous incentives are also remaining .Pls tell me what can I do