Principal not ready to sign form 112

Dear sir, i have completed my articleship in november 2014. i did my cs executive and mcom during my articleship period. i was not aware about form 112 that time. my principal gave me leave for exam days which i compensated by sitting extra or on sundays. i cleared my ca final in november 2016 attempt. i applied for membership in 1st week of february. i honestly revealed that i did my cs and mcom in the membership form. i got a mail from the institute that form 112 was not filled by me and so i have to fill form 112 with condonation letter by me and letter by principal that i have attended office. my principal is now not ready to sign the form and give his letter and is telling that he wasnt aware that i was persuing those courses. what recourse do i have? is my membership in danger? please help.