Pay protection case

I worked in a central Govt Dept for 2 years and 9 months. I had applied for Technical Resignation on account of my selection in some other Department of Central Govt. The resignation was accepted by my previous employer and I was relieved from the dept with technical resignation. However, prior to getting relieved I was not given the confirmation order i.e. the probation completion order through the probation was of mere 2 years. All though I fulfilled all the required conditions for one’s confirmation in the service but the administration had not processed the case till the day I was relieved. Later, after my resignation they did not pass my order and told me that the names of employees who have left the department are not considered for confirmation. In absence of the confirmation order from my previous employer my new employer is unable to give me benefits of past service. It is requested that I may please be advised. Is it possible that the previous employer can deny me the order even though I was not at all fault? Should I think of knocking the doors of CAT?