Reserve Bank Of India [RBI] — Regarding transaction tax

Address:

Surat, Gujarat, 395006

Before few i go for shopping in garment shop at that place after buying shirt cashier says that if give payment in cash then you have to give 650 or if give payment through card then you have to give 2℅ more on 650, what the hell ? If i goto dmart or in bigbazzar then there is nothing like this ? They are saying that we have for for transaction. We don't about more in this please say us correct things.