If a customer returns the goods, then he will be credited only for the sales price of goods or also with the sales tax? Customer will always be liable for sales tax, even if he returns the good?
If they return the goods then they are credited with the full amount, including the sales tax.
(The supplier will have paid the sales tax to the state when the goods were originally sold. When the goods are returned then they get the sales tax back from the state (usually by reducing the amount they owe the state on other sales))