Monginis Cake — Rotten Rasmalai cake

Hi,

We purchased Rasmalai cake on 22 May 2022 from Monginis Bhandup west branch.
The cake was rotten and smelling
We returned cake and shop owner confirmed to give replacement of that cake.
When we purchased another cake they said we need to pay extra 100 rs for that rotten cake as per company rule.
Ideally this is very wrong as the cake was rotten.
Kindly help on this.