Double charged and refused to be refunded

I placed my order and at the point of payment I was double charge.i notified the staff immediately and showed them the proof.i was told it should return.i waited for a day no refund.i call the store to let them know that I haven't been refunded.they told me their is nothing they can do i must go talk to my bank at that point I just knew I'm wasting my time with this store and I told my self to cut my losses and eat somewhere else in future.