Can we rely on Sale Agreement after purchasing property (flat) without registering it as we want to avoid registration charges. We would like to sell in 12-18 months period

Actually I am in the government engineering college in kolkata , west bengal. I had allergy and asthma and did not stay at my hostel in 8th semester as of now this is march and three months have passed. Although my previous dues are clear the administration is asking me to pay mess fees for the 8th semester too. I know it is my fault that i did not inform them about me not staying anymore. But is there any way I can get out paying that hefty amount as I did'nt use the service or ate food.

A builder(Deceased) sold common stair case area as a shop in 1986 to my father(Deceased) and said he will make the changes in building plan and provide us with a sale deed but he has failed to do so , what should i do now ? i need to regularise my shop needs it's sale deed to be made.

Dear sir I have filed civil case for declaration of title suit and the respondent is holding unlawful possession and claiming owner of the Land base on Void documents, therefore kindly suggest me supreme court judgement citation for Void documents . please give me citation of supreme Court judgement over Void documents And also the lower Court has rejected my injunction petition citing the reason that there is no balance of convenience, no irrepairable loss and No prima facie case, Kindly give me Citation of supreme Court judgement so that I can give citation of supreme Court judgement in the lower court in order to strengthen my point.