GMT 2 Purchase Gone Wrong. Need Advice Please!

[Banjo Man]

I am living a nightmare of sorts. This was supposed to be a very special day for me, taking delivery of my first Rolex, a GMT Master 2 BLNR. I purchased from a jewelry store which I found through Chrono 24. The price was good, I looked up the company and found good reviews, talked back and forth with them, everything seemed fine. I paid over the web via master card on Tuesday, the watch was to come fedex today 7/10.
I arrived from work this morning and checked the fedex tracking website. It showed the watch being delivered to Hoboken NJ, and I reside in Miami. I began to get vey worried. I attempted to call the store, but got a voicemail. I called the salespersons contact number and got no one. I finally was able to reach some one affiliated with the store, but it seemed as though I was talking to a stranger that had no idea what was going on. I was starting to really think that I had been scammed. Then I started receiving text messages from the salesman that he was looking into it. I pleaded with him to call me, but he never did. I just wanted to hear him tell me that everything was ok. But I could not even get that. An hour later, fedex shows up with a small package, very light. I knew there was no Rolex in the box. Inside the box was a diamond engagement ring. GIA appraisal value of 20k. By now the store was open and I was able to talk to someone. They very nonchalantly explained that there was a mixup in the shipments, and would I be so kind to take the ring to the local fedex office and ship it back.
Before I tell you the rest of the story, what would you have done? No watch, no money. And as soon as the ring is shipped, no collateral of any kind. All the while mind you, everyone who represented this place comes across as shady. The salesperson was talking to me the whole time on his cellular while getting his car repaired at the local garage. Doesn't exactly instill confidence. Anyway, what would you all have done if you were in my shoes?