I had to leave the company only after a day due to medical reasons

I joined an IT company but immediately after the first day I experienced pain in my bladder. I understood this could be due to a bladder stone for which I was taking homeopathic medication. I informed the company hr that I cannot work due to medical reasons. Also sent them some medical reports which showed there was a bladder stone. The pain that occurred to me was unexpected. Since people do work with bladder stones. They asked for latest reports but I was not willing to send them latest since it was an expensive test for which I was not willing to pay. I could not attend the office any further but send them a mail for discontinuation. After a month I had surgeries of my left kidney right kidney and bladder. I was admitted to hospital for 9 days. After almost an year this company sends me a notice to pay the money equivalent to notice period. I explained them my medical situation and sent relevant reports including my photo in hospital. They acknowledge the mail and still sent me a notice after another year asking for money. Isn't this harrasment when I went to company for just a day . I don't own any assets of the company. How can they force me pay the amount when my reason of discontinuation is do geniune. What should I do?