Experience letter & FNF if left company without serving notice period

Hi, I have a question regarding the employment. Currently I am working in an IT industry since June, 2018 and I have a another opportunity for which I have a joining date on 2nd April, 2018. But the thing is that I have a notice period of 3 months i.e. 90 days and my new employer wants to me join by 2nd April. I already resigned on 9th Feb and currently serving a notice period. Even I asked my manager to release me early as there is a buy out policy and told him that I can serve till 27th March. However, he is not agreeing for the early release even though there is a buy out policy and gave me one condition that if someone joins the org as my replacement then he can release me on that day only. But I have a concern that if no body joins the org within that period. And I decided to leave... Will that be considered as absconding?? And whether I will be given my experience letter for the period (18 months) which I served till now in this org after completimg all the dues and FnF?