Monginis Cake (Mio Amore) — balance amount not given

Address:

Kolkata, West Bengal, 700071

Honestly it was bizarre experience with this russel street mio amore cake shop. On 10th sep, 2018, i had purchased one chicken 65 & one cheese omlet sandwich in lunch time (Precisely at 13:55 hrs), after that rs 500 note was given to one of their staffs (Name: santanu chakraborty). As my total bill was rs 75, he gave me rs 25 as balance and rs 400 was not given. I was in hurry that time and i left the shop immediately.
During the time i was leaving office in evening, i checked my wallet that rs 400 was not there. I can clearly recall that only 2 nos of rs 500 note & few 10 - 20 rs note was there when i went for lunch (There was no rs 100 note). After realization, immediately i rushed to the shop in evening. That time one new staff was there in cash (Mr abhay giri) and the other fellow was also present. Once i explained them all this, mr abhay said he need to check the cash for day. Surprisingly other guy smartly told me he has given me complete balance. My question is 'how he can be so sure after dealing so many customers?'. Normally he should tell "we need to check". Even i asked them please check the cctv footage of 13:50 to 14:10 hrs, it will be clarified. They said no cctv is there. Only way is they will check the cash and confirm.
So i waited for next day and went today again in lunch time. Today i got answer that cash was ok, no rs 400 additional found. After several discussion, it was very clear that they are not going to return my money.
My only concern is if cash was ok for the day, then there is two options left: 1. I am telling lie, 2. The guy who was there in cash, has done it intentionally and kept this rs 400 in his pocket. If 1st option is true, then i would not writing such long story and wasting my time.
More importantly how cctv is missing in such a busy shop in busy street of kolkata. If it was there, then it will be clarified then and there.
I know i am not going to get my balance money back, as i did not have much proof, but its all about the integrity and transparency. It was my fault that i should count the balance, but at the same time it is expected from good brands like mio amore.