Parryware — VAT collected, retail invoice has less amount compared to the VAT amount collected, bill provided for less amount

Hi Sir,
I purchased items of Parryware from one shop, which collected money and told me to go back home. As items will be send via transport and bill will be provided along with that person. He provided me a paper note where the calculation was done. On delivery of items, I found that retail invoice was less than the amount on paper note. The shop keeper collected VAT, but did not provided the bill to me.

I have details of the shop keeper name and address.

Kindly advice me next course of action.

Regards,
Shiv