We're sorry, but from your note, it's not really possible to determine what caused your model to crash. If the retract or throttle servo "hung up", a lot of current could be drawn from the battery pack, causing low voltage. The receiver would quit working as a result. You mention that the throttle servo was DOA. It could have failed prior to the crash. A shorted servo could pull enough current to cause enough of a voltage drop to make the receiver quit.

It's possible that you got some kind of interference. It's possible something in the receiver was intermittent. And so on.

If your transmitter has a difficulty, then it's possible that it contributed to the crash.

We can examine a system after a crash and say what's wrong with the system as we see it, but cannot always state what the cause of a crash might have been. We would suggest that the system come into the service center for checkout.