Job offer given but they dint do the onboarding on the mentioned date

Hi Shavetha, I am an IT professional from last 17 years and I worked for Infinite, Nokia , Oracle and Abjayon, I got a offer from Tech Mahindra 2 months back and I resigned and served my notice period to join Tech Mahindra and I was suppose to join on 16th of July 2021. I have submitted all the document on the date on joining (16 july 2021 Friday )before 5 30 pm . I got welcome call and congratulation call also in the morning. But I dint get my employee id and email credentials. When i asked for it by mail i dint get any response on on Monday morning I got a mail to sign an amendment to join on Monday the 19th of July for which I refused and I replied them to make my joining date as 16th July only . All in vain I dint get a response on mail then I followed up on calling asking for update . They said are working on it and this got dragged to Thursday and on Thursday the called and asked to take offer on Friday 23rd July or Monday 26th July and accept a 50k joining bonus with out tell me the reason and why they delayed my joining. (This joining bonus of 50 is also with 2 conditions and they said if dont accept then I have to forego my Offer from them. Kindly suggest me a forum or legal action to be taken against what i all agony and pain I have faced . Regards Sridhar Reddy K I have Finally joined