Central Board Of Secondary Education [CBSE] — harassment

Sir i am a teacher appointed in a school as pgt commerce since 2013 with all qualification and when i was under a treatment for pregnancy, conceived after 14 years of my age school principal denied to give me maternity leave but i still sent a mail for maternity leave for 3 months for the acknowedgement in school id but they didnt replied. When i wanted to rejoin they already hiered another teacher with no b. Ed and no experience and not allowed me to join.in next session i joined but they didnt give me my classes and demoted me.in next session when i asked principal to give my classes back to me he denied and again he preferred that teacher. Its mine 7th year of job and still not having any security where i sm on my 38th year of age. Kindly guide me with your rules and guidelines about regularisation. Iam sufferring from this harassment year by year. After your reply if you can help me i will disclose my identity and school name. Kindly helo