zara refuses to help their own customers

Received a shirt from Zara as a birthday gift which is too big for me( the price tag is still on the item) both eastgate and mall of africa zara refused to exchange it , NO receipt NO help .. and the person who bought the gift throw the receipt away so i guess it was a waste of money

Note store mangers were incredibly unhelpful , Worst part is i actually shop there , well no more