Pay protection

I was initially appointed as a Police Constable, in Puducherry on 01.04.2005( Pay scale -[deleted] + G.P 2000) . Later on, i was selected to the post of UDC through Direct Recruitment, I tendered my resignation of the post of Police Constable on technical formality in 12.10.2010 and joined in the post of UDC on 13.10.2010 (Pay scale -Rs. [deleted] + G.P.2400 and his pay was fixed at Rs. 7510/- + G.P. Rs.2400/- w.e.f. 13.10.2010.). Now, In my previous post i.e Police department my basic pay was revised and refixed my Pay Rs.7830/- +GP 2000 on 12.10.2010 at the time of my relief from the post of Police Constable. However, after my appointment in the post of UDC on 13.10.2010, my pay was fixed at Rs.7510/- being a minimum pay of the pay band of Rs. [deleted] + G.P. Rs.2400. resulting a loss of pay of Rs.320/- per month in his basic pay. In my department old department i.e Police department 7830+ GP 2000= total 9830. New department UDC Post 7510 + GP 2400= Total 9910.. They said that pay protection not eligible for you. because of u availed higher salary in UDC post.i.e Rs. 9910.. Question 1. can i eligible for Pay protection Rs. 7830+ GP 2400. Question 2. please any one clarify pay protection means Pay band + GP or Pay band only???