Non-acceptance of examination form.

My name is saliq javaid bhat.I am a student of Kashmir Govt Polytechnic Srinagar pursuing my civil engg diploma in 5th semester.I have been a good student in academics and always got good grades.During the 5th semester my health got unwell and i missed my most of academic classes which resulted in poor attendance.i was diagnosed with generalized anxiety disorder and gastro-esophagel reflux disease.i went to the head of the department with my medical certificates and submitted them.but unfortunately when the shortage list came out the cut off was taken 75% and my attendance percentage was 50%. I discussed this issue with principal and HOD and came to know that my medical certificates were not entertained.I was detained and not allowed to submit my form for the issue with HOD and principal again, they told me that they can do nothing in this matter, & I should get written description of allowance from the higher authority such as Minister of technical education etc.I went to the Minister of technical education with all my medical certificates and he verified my documents and signed/stamped my letter for accepting my examination form.But unfortunately when i went to HOD and principal again they refused to accept my form by giving me a ridiculous reason that there are 60 student which are detained and we can't allow just one or otherwise the other students will create an issue out of this. my two and a half year of academic career is on risk.Now i want to know what are the legal steps that i can take in this matter to resolve it.