Dear Rupeshdelhi
Simply being Terminated by the company, is no reason for denial of gratuity.
Even termination on Misconducts is also not a reason; for there are many misconducts which are not considered serious or call for major punishment like Termination.
Also, the company has to prove the Misconduct through a proper Enquiry which adheres to the Principal of Natural Justice.
Moreover, the Enquiry has to be of quasi-judicial in nature; which very few companies have the know-how to conduct.
From my experience, I can tell you that the company shall be forced to give you gratuity in case the matter goes to court (other things being true as stated by you).
The very fact that, ex-employees do not fight for their rights, encourages these companies to be arrogant enough to violate Laws.
Warm regards.