They Cancelled Order and No refund

I placed an order on the 18th for my son’s sneakers and made a payment for them , delivery was meant to take place on the 20th as it showed on the App and it ddnt happen and when i called the customer care they only then told me the order was cancelled due to no stock and I would be refunded it’s the 27th today and there is no response to my emails and iv been on their line for 10 minutes and no one answers , this is pathetic more especially since they dnt even bother to communicate or advise that there is no stock but they took my money anyways