Reliance Trends — Exchange of my item

I have got a gift from someone few products from your lucknow store. I was facing choice issues then got that exchanged by my mother...Now i have size issue (trouser and top) both are small ..i need one size big, that was available also at the store but store person said no exchange now..
Pl help me out both (trouser and top are of no use as they are small in size ...