Consumer Redressal

Dear Sir/Madame i went to forum shopping mall on elgin road on 13/02/2015 to shop at a store called tommy hillfiger. i bought 2 tshirts for children at a 40% discount.on the MRP they gave me 40% discout and then added VAT @ 5%. how can tax be added on MRP after giving discoutn.i have the bill with me do let me know when i can scan and mail the same to you. all shops are resorting to this practice where they say 40% discount plus vat applicable.i feel i was charged extra as no sort off tax whatsoever can be charged over MRP.i would request you to kindly advice and look into these mall who are cheating customers.