UPDATE:

Eventually, Wayne at Tuneboy did finally get back to me with a reasonable explanation for the long delay, and the product did finally come in today so I made sure the credit card dispute was retracted. The initial communication response time of over 2 weeks has also been much better over the last week or so, which has made it a lot easier to sort this fiasco out. I can't say much about the product itself yet, or the ongoing support for it, but I can say that, in this situation, Tuneboy rectified things to my satisfaction to the point where I'd no longer be hesitant to buy something from them down the line.