Termination from State Bank Of India

I was promoted from clerk to officer at State Bank of India. my mother fell seriously ill, I applied for reversion of my promotion and leave. I did not obtain an acknowledged copy of my request from my side bank. I continued to work, putting in 16 days during an audit at my branch and 25 days during the DEMONETISATION period within a year of my promotion.After 15 months, bank initiated disciplinary proceedings under rule 58, but no action was taken. Four years after my promotion, the bank terminated my employment under a different rule, rule 40, without completing the disciplinary proceedings under rule 58. I received copy of my application albeit without the necessary enclosures. The bank used this as grounds to dismiss my application, claiming that I could not apply for reversion once I had opted for a promotion. Service Rules Handbook, clearly outlines reversion from officer to Clerical Cadre, within one year of promotion. Is my termination valid?