I agree with all the Silversurfer said, but to try to simplify things, first run a test with a single receiver turned on, this should be easy enough. I normally require that I get at least 150 feet with no glitching with engine running and one segment of the antenna showing on my Futaba 9C.

If that 1 receiver passes, try again with both receivers turned on. If no change, and everything is solid, you can fly.

Most worrisome is the one test you made when nothing worked. This points to an intermittent connection or component. Do not fly that way, you must be sure it's all solid before you fly.

If the range test fails in either single or dual RX, try it again with the engine off. If it fails that way there's something seriously wrong.

TF