How to get my experience letter, salary and loyalty Bonus?

My company terminated me 2 months ago. I was doing work from home that time. They haven't gave me my experience letter, salary and 13 months loyaly bonus. I almost worked there for 1.3 years. Now when i asked them to give me my exp letter and salary with loyalty bonus. They are putting wrong allegations on me that i had instigated other employees against company\s policy and working environment and pressurising me to send apology letter they mailed me this wording( write an apology letter for your misconduct against Company policies. Further we reserve our right to take appropriate action against you for any act or omission committed by you during the period of your employment with us which come to our knowledge later point of time and also in event of any claim being raised by any person against you, then you shall be responsible and liable to) I have done nothing wrong. if i send them the apology letter i am sure still they will not give me any letter and salary instead they will use my apology as a evidence. Please suggest me what to do. Thanks