I worked with a small scale IT company for close to 18 months and due to an accident, I had to leave the company in October 17. Back in March, I had received an increment. After a couple of months of being bedridden, the company did not employ me again as they had already found a replacement and subsequently became uncooperative. I had to gain my experience letter from the HR after faxing a lot of problems.
Now I joined another company in late Feb'18, and for the BGC, my previous manager refused to acknowledge I worked with them after march'17 on the grounds that I couldn't serve my notice period hence they can only accept my tenure till March, when I got my increment.
I have the original offer letter,experience letter and the salary slips. What I don't have is the increment letter (since it was a small company, they didnt provide it to me, and I admit I didn't pursue it a lot either). The company I have joined has asked for a mail from the previous company, but after numerous attempts, they are not ready to clear my BGV. If my BGV cokes as RED, I will lose almost an year of my professional career and possibly more, as I won't be able to show my previous company'S credentials to any future organisation.
What should I do? A couple of people suggested suing my previous manager but as a last resort. What can I do before that to ensure i can continue my employment with the current organisation?