Hmmm a complete loss of control when in flight, after days of perfect control followed up by good ground checks....

To me; it sounds as though something electrical has worked itself loose.

It is making connection on the ground but it breaks down in flight either from the increased demand or from the vibration... either way double check all wires and connections.

As a last resort send the receiver off to the factory rep. for an inspection - it could be an intermittant receiver....

Good Luck!