What step can be taken for wrongly accused as an absconder by employer

Iworked in a IT company, bangalore,India for about 3 years. my notice period was 2 month, already i had 20 leaves. I resigned my duty on 6th april'18 and i requested management and hr to relieve me asap. thus initiated a mail thread with HR. On 11th May'18 (friday)HR agreed to release me next week i.e 14th may as such mail received by me stating clearly you can get release date on next week (no date mention). I fell sick and given them medical certificate for 14th may (monday) stating i am ill. therefore, i joined my new company as they have accepted my mail (medical leave) salary was blocked from April month onwards ( which shouldn't be there as last month salary should be block for full and final statement)After few days on 23may'18 i received call notice & on 7th june i was terminated stating absconder .please suggest