Calzedonia's Unqualified Workers Refused to Process a Refund

I bought many products from Calzedonia on the European side (Tesvikiye) of Istanbul. Two days later I went to the avm called Piazza in the Anatolian side as I wanted to change one of the leggings because the size was bigger and I wanted to give back the other one as it was too short for me. I waited for 1 hour for them to change the L sized leggings to medium. They told me they wouldn't be able to refund the other leggings because it was bought from the European side saying that they have a different pos device. Upon me insisting they contacted their accountant and I filled in a form but I still couldn't get my money back. Before I filled the form, the director called N**** went on a break and I waited for her return for another hour. I immediately ask for my money back and want the store workers to be warned and penalized. This is not how consumers should be trated!