I had the same issue happen to me yesterday. Everything was normal with the flight, other than it being the 13th flight since I've had the Typhoon H (TH), and when I was preparing to land neither landing gear came down when the landing gear switch was moved to the down position. I hovered in place about 5 feet above the ground and captured it around the retracted gear legs and motor arms and throttled to idle. Of course at that point the gear began deploying so I had to quick reposition my hands to keep from dropping it.
I tried troubleshooting by placing the TH upside down and cycling the gear. Each time it worked without a problem. I also flipped it right side up after the gear had been retracted and it deployed as commanded. I checked the switch indication on the ST16 and it indicates properly for the position the switch is in. I also looked at the Remote Flight Log (Ch10) and it gives an indication that the landing gear switch on the remote was activated. Don't know if there is a way to check if the signal was received on board the TH. I also seem to recall that during the flight that possibly right after the gear had been retracted I saw a flash or two of orange from the rear indicator light on the TH and don't ever recall seeing that before in flight.
I think if this happens again, I will first try a max descent rate with a quick reverse to max climb rate in an effort to g-force bump the gear down. A new procedure to add to the emergency check list.