Take money but don't deliver

Placed an order for plants which were clearly marked as In Stock. Paid the full price plus transport costs. Received confirmation that the plants would be dispatched on Monday. By Friday, nothing had been received. When I called, I was told that the plants in stock were of poor quality and that they were waiting for "replacement" stock. Received no indication of when the plants would be delivered.

Highly suspicious behaviour and I'm not holding out much hope