Tata Consultancy Services — negligence of tcs while recruiting

Hi i have been recruited in jan 2018 in tcs. While interview process verification was done by the hr's. They didnt say me anything during interview process and finally i got selected. But after my joining, after getting permanent id card, they are saying that mine is not 60%. Acc to mumbai university 6.75 cgpa is 60%.
6.75 is mentioned in my provisional. My agg cgpa is 6.72 mumbai university rounded it off to 6.75 and that is mentioned in my degree. But the tcs hr team is now creating a problem to onboard me. I left another job for tcs. I spent too much money on affidavits agreements hostels etc... Now tcs has planned to terminate me. They dont have any rights to fire me without a valid reason. And if theres a reason they should have fired me during interview only when the verification was done. Please take strict actions on them and now i am going to police case this issue