Pay protection

I had been working as Scientist B in Central Silk Board, Ministry of Textiles, (GOI) with a capacity of [deleted] and as per 7 Pay commission, level is 10 from November 2015 to April 2019. I applied for the post Assistant Professor in Acharya Narendra Deva University of Agriculture and Technology (State Agricultural University), Ayodhya, U. P. in 2019. My joining was technical resignation and joined immediately next date after relieved from my past job. Then I approached administration with proper written documents. However, it was totally futile and my requisition was rejected. My present post scale same i.e. 15600+6000 AGP and same level in 7 CPC. There point is to rejecting my application is grade pay is different and not at all equivalent to the present post. I request you to ask how to protect my pay. Whether am I eligible or not and moreover, can I approach for past service counting since the scale is same and only difference is grade pay. Please give the right solution for the above situations.