Kim Wang Asian Grocery

I bought a bag of pre-packed dried shrimps from Kim Wang. Realised they have gone a bit green and mouldy even though the bag was still sealed and unopened. Tried to return the item but the owner was so rude and offensive. They were not willing to provide a refund or exchange because I had lost my receipt, although the item still has the shop's name, the price sticker and expiry date. Both the owner and their relatives displayed such rude attitudes.
Worst service ever and rude owner response! They don't even deserve any star rating. I will not go back to shop there ever again.