Can a company retract their offer letter

Nearly three weeks back, I received an offer letter for a full-time position in a company. I received this offer letter after multiple rounds of interview. The offer letter had mentioned the need for immediate joining due to which I had to leave my current job. Due to a few health issues I had asked for the joining date to be extended to which they had agreed and asked me to freelance for the company till I was well and able to join full time. The COO had asked me to email her the date on which I could join. After a week I informed her the details of when I could join following which the COO replied that the offer is not yet confirmed. Despite handing over the offer letter, they have not yet confirmed my position nor allowed me to join the office full time. I am now caught in a tight spot having left my current job. I have also not received the payment for my freelance work. Is it legally possible to retract an offer letter? I have not made any false claims on my resume or during my interview. Is it possible for me to take any legal action against this company on this basis? Here is the exact text in the offer letter (Names have been withheld for reasons of privacy) Hi *****, Congratulations! We would like to extend an offer of full time employment with ***** ***** as Content Associate Important Details of the Offer and Employment: - Designation: Content Associate - Monthly Compensation (cost to company): INR ******* - Working days: Monday to Friday - Start date: Sometime this week - to be discussed with ***** Would appreciate an acknowledgment and acceptance reply to the offer by Sep 13, 2017. For any clarifications or questions, please feel free to email me - will be glad to address any queries. We look forward to having you on board the ***** team. Best *****