Termination

You have initiated many threads. 

Many of the employers insert in appointment letter, service rules that employment can be terminated due to long term absence even if due to sickness.

Apparently your leave intimations were not accepted and leave is not approved. IN such a case it might have been treated as unauthorized absence, which might have been treated as misconduct.

If termination is effected due to misconduct then employer may not tender notice pay.

You should spend quality time with your labor consultant/service lawyer, show all of your docs, give inputs in person.

The lawyer that has examined your docs , records, inputs can advice you the best.

On line discussions have its own limitations and more so in matters that may require in depth analysis of documents and inputs.

Being a Trainee LLB you may appreciate that info and advice in bits and pieces may not help you much.

You should not hesitate to approach a competent and experienced labor consultant/service lawyer.