Mother dairy outlet cheating retailer

The outlet is located at IARI pusa, near girls hostel. We are buying from that outlet for the past five years. the retailer who is at present is not good.
The outlet owner and his assistant are cheating in giving money as change. This is the second time. I was not having any change money and took a 100rs note from my purse to buy milk and a cool drink. she gave me change only for 50rs and shouted like anything stating that i gave only 50rs and asking change for 100rs. This is not the first time. second time it happened. Last time i thought it could be my mistake. But now its proved that she is cheating many like this. My friends are also complaining about them like they dont give money and give cards written with 4rs, 5rs like that later they refuse to give money saying that its not the one given by them. if we buy in bulk some materials like one curd pack or one ice cream they put less in the pack and they take money for everything. Even if we go and ask in 2 min they refuse and say that you have taken everything and left nothing here. even we dont remember that whether you came here or not. we are facing lot of problems with the persons at present. change them as soon as possible. there is no need for a scientist who earn lakh rs per month to say a lie for 5rs or 10rs. If you are putting worst people to spoil our peace, then we will be forced to take necessary action against them in future. please kindly avoid inconvenience.