P.c Chandra Jewellers — Cheated on Hall Marked Gold

One Noah (Hall Marked) which was purchased from B. Sirkar Johuree Pvt. Ltd.almost five years back so for the exchange purpose I went to P.C.Chandra Jewellers at Kanchrapara Branch on 11/3/2015 to purchase a new Noah against the old Hall Marked Noah. But the problem is that no one of the shop want to see the old bill, straight away they were deducting 2.330 gm out of the original weight of 9.830 gm. by stating the reason of deduction that they were not finding the Hall Marked sign on the Noah whereas in the old bill of B. Sirkar Hall Marked was clearly mentioned. The New Noah delivery date of P.C.Chandra was on 7/4/2015 which I collected from the shop on 8/4/2015 and the weight was 9.90 gm for which I have to pay Rs. 11.056 extra. How they are deducting 2.330 gm of Gold from the Hall Marked Gold? I want either Gold or equivalent of money back. They cheated like this. I have both the money receipt in my hand.