Denial of noc by institute, stated that according to our service record you are not eligible for job

Respected Members I am Central Govt employee, I applied for another govt job, by giving due intimation to my office. Criteria required for the job is 5 years(out of which 2 years is govt experience mandatory) and Post graduation. My Office denial my NOC request stated that , according to our service record your total experience is 4.5 years and your qualification is only graduation. Here it is important to mentioned that, due to Bonafide mistake, i haven't mentioned my post graduation degree and previous one year work experience in my attestation form during joining. My office HR stated that, any additions of degree and qualification must be done before closure of probation. My probation is already closed. Now they refused my NOC request. Although, i shortlisted in another job, for which I applied for NOC. I have required experience and educational qualification but the thing is the same is not updated in my current office service record. What should I do know. Can my current office legally denied my NOC on this ground ? Can is there any provision, that we are not amend our service book after closure of probation. Please give your valuable suggestion.