Appalled beyond believe

Was at Identity Westwood. Purchased a jumpsuit that was hanging in the store on a rack with the sale items whilst waiting for my online order to be retrieved at the back office. When the online order was brought to the till, the lady bringing the package noticed the jumpsuit that I just purchased and insisted I had to return the item because another lady called and asked for it to be kept aside. She proceeded to credit my account immediately. Important to note it was a sale item (which I've previously been told that they are not allowed to set sale items aside) and it was on a rack in the store. In the moment I was completely shocked and extremely upset but didn't react. But I can't believe how appalling her behavior was. Is this Identity's policy on how they run their stores?