Well that's your own fault for not reading the information properly. The front page clearly says "OS X: Soon". I personally have paid my licence fee in anticipation of BraCa doing the same amazing job he does every year with iFMRTE. But he is under no obligation to do so, you however, should read what you're buying before you pay, not moan about it afterwards.
The Mac version always takes longer, from my understanding it is harder to get the programming correct and, from a business point of view, most users (and therefore a majority of funds which are needed to build FMRTE) are Windows users. I would rather allow BraCa the time to properly develop the programme and deliver a good product, rather than a product which is going to corrupt the game or cause issues.