What to do if terminated without genuine reason

On 31-August-2018, I had a dispute with manager of other department. He assigned a task on technology on which i worked before one year and 4 months. I informed my manager please assign this to person who has experience and working on that technology for me it is like revise all and it will take time. Then he both discussed and that person came to me asked How much time it will take.I said same.Then he said i have 12 year of experience in this technology,even i can do that. Then i said so do.Then he said what is your need to be here. I said i ll let you decide.Eventually he said do you want to be fire or terminated? In anger or flow i said do it. He said think that i said yes. Then i got a call i picked that call and left the spot. after that i drop a mail on 2-August-2018 in which i apologized but on 3-Aug-2018 they said to we are terminating you due to misconduct on floor.We can not give experience letter to you.I did not sign on termination letter as well the cheque they were giving. What shall I do?