Refusal of refund, violates and bullies customers

I bought a dress 2 days ago using my debit card and Miladys is refusing to refund me (either cash or putting funds back to my debit card) I don't have full slip. I have got the second part of the slip which shows the at the back (1)Miladys. And at the front (2.)Walmer Park shop 328 (3) Retrieval Ref No 4. Payment reference 5.the amount I have paid 6.Transaction ID. they are telling me they do not have the bar code slip but the barcode is on the tag on the dress. The amount on the slip is the same amount that I have paid. I feel ****** and violated, bul**** as a customer by a shop I used to trust.