Punjab State Cooperative Milk Producers Federation / Milkfed Verka — Milk

I am residing in sector 79, mohali.
Here is a verka booth near my house and he sold me verka cow milk 1.5ltr at a price of Rs.72. The next day when I asked him that its price is less and why you are selling it at higher price than MRPA. He told me that he will only sell at this price, either i buy it or not and also behaves very rudely and also uses harsh language.
If you can look into this, please do.
Thank you.