I've usually had to leave a message for them too. I have sent them an email so, once I receive word back. The newer L-model has the chipset the iFly 700 needs to connect via USB. They had said their new batch would all have the new chipset.. Just make sure you don't buy a used one if looking to use on the 700 via USB. All L models new and old would work on the 720 via W-Fi. Hope this helps.