Difficulty in getting experience letter

Dear sir, I have been working in BMBirla heart reserch centre since21 march, 2015 As a staff nurse in critical area between I went for govt job interview for which I applied leave which was not approved and I went anyhow..which was later adjusted with my day off. Then again on 3rd oct 2016 I have to appear for military nursing exam so I went I submited application but that ws not approved too.during which I undergo medical screening after my interview and I was diagnosed with gall baldder stone n I was given chance to appeal for it...so I appeal to army medical board and I informed my incharge in my unit dat I will be undergoing surgery so he said he will inform it to our assistent nursing superintendent so I was relieved and focussed on ma surgery so before coming back to hoapital I called ma incharge he direct me to meet chief nursing officer..so on 7th I was found fit by my doctor and on 15th I went to meet my CNO and I was told that my employment Id is no longer valid ol your PF is gone too and your experience too..if u want to join then you have to join as a freshyear...as I ws olrdey on notice period I submited my resignation on 21st june, 16 and again extended it writing till I will receive my call letter..then again on 16 I went then dey said to cum tomorrow o I wrote grievence to HRDept...then I had meeting with HOD HR , CNO on 23rd nov, 16..den dey gave me option that you have two options 1 u can join as fresh year then work here for 1 year and we will give you your 1 year certificate plus previous 1 year 6 months experiene or else we will give you your certificate but writing all the disciplinary offenses you did.and on next day I said fine I need my experience certificate so dey kept me waiting whole day ...and todays its day 14th since I came n still dey kept me waiting for giving my certificate. Am I eligible to threaten them saying I woll go legal its a harassment