Forced resignation

Sir I have employed in pvt charitable trust, in u.p. since 1996 to 2020 as a permanent post continue same institution. Last year in june 2020, employer issue chargesheeted with suspension letter and asked me its submitted my clarification within 3 days. After I have submitted my clarification, employer call me at Office for discussion chargesheeted suspension related matter. I have come to employer management chamber, they forced me immediate resign from service otherwise he terminate my service which loss my Gratuity fund. So I have sign resignation letter, gratuity check amt. etc. and then employer immediate accept my resignation and its copy received me. After forced resignation, I have complain DM, SSP, Labour Commissioner take action against employer. Then after 15 days, I have write/case CPC_ DLC and thereafter DLC heard both side argument, he order forwarded hearing case to Labour Tribunal. My question is, During suspension period, disciplinary case pending, without serve notice period, immediate resignation letter accepted by employer at same date is right? My organisation employee service rule govern through his Standing Order. Standing order mention that an employee if resign his service, serve notice period 30 day.