Try rebinding the transmitter to the receiver with everything back to default settings. Then recalibrate everything all over. If you got throttle and reverse to work fine in reverse mode then that means it's not an ESC/motor direction issue some transmitters have to be in reverse mode for the throttle channel to work right (like Futaba).

As far as only being able to turn one direction that is very odd. I'm sure you didn't get the ports mixed up on your receiver. But double check that anyway.

Doesn't sound like a steering servo issue to me...if you have another radio system to test the steering servo then that will eliminate the possibilility of a fried servo.

Could potentially be a faulty receiver if you have already gone through your own testing already.