Bad service

Ordered pampers from mr D it was not stated on their app that they sold out,money was debited only to get a message that order is canceled due to sold out,tried to get my money back they said Im gonna get it after 3 days,I dont have money to go buy when I ask for my money they say there's nothing they can do,ive got a baby with a runny tummy I need the nappies now dont have extra cash to go buy actually im angry cause thats my money it takes them a few seconds to debit but 3 days to return it back its my money I want it back