Metro Mattress refuses to cancel my order despite nothing being delivered

I ordered a mattress from my local Metro Mattress in late January and paid in full. Since then I've heard nothing from them despite calling 4 times to ask about my order, each time getting a new excuse. They finally gave me a date for delivery but when I called the day before the delivery to confirm they stated the mattress was not in stock and it would be 3 more weeks until they'd have one for me.

I went to the store in person to cancel my order but the store manager became irate that I wanted to cancel, crumpled up my receipt and told me that he "didn't have to give me back my money" and cited their "No Refunds" policy. I stated that since nothing was delivered this is a cancellation and I'm fully within my rights to cancel.

At this point the store manager lost his mind and started berating me personally for cancelling. I chose to walk out of the store.

I called their customer service department who told me that the only way to cancel my order was to go to the store and do it in person. I explained that I'd already done this and explained my experience above. They told me unfortunately that is the only way to cancel an order.

At this point I'm a bit stuck, the store manager is refusing to cancel my order and the corporate Metro Mattress support is telling me I have to go through them.

My first thought is to talk to my bank and request they revert the charges. Any advise?