1. It is not clear whether you had given any written presentation for leave and the same was granted in writing as well.
2. if not then the management can very well take plea of unauthorised leave to suit their objective of cutting manpower.
3. if there is written proof then the termination is illegal and you can challenge it in civil court.
4. Since such remedy is both time taking and not so cost effective you should thin twice on filing the civil suit.
5. So amicable settlement and honourable quitting with compensation is best found solution for you .
6. To rod the management to settle the dispute with you, send them a legal notice.