Let me see if I can get this straight: The main rotor on the LMH spins counter-clockwise (seen from above), thus exerting torque on the frame in the opposite direction.

Hence: If the heli itself spins clockwise, and yaw input does not achieve anything, you are not getting enough speed on the tail rotor.

Then it is possible that setscrews somewhere are lose: either those holding the TR to the TR shaft, or (happens quite often) those holding the black (front) gear on the TR wire.
Try holding the main rotor and manually spin the tail rotor. If you can do that, it is either the setscrews, or one of the red gears (aft on the TR wire and on the TR shaft) has come lose or has stripped. In this case you would have to replace the part in question, as there are not setscrews you could tighten.

If the above description does not fit your problem, please describe in more detail.

Oh yes, and try to stay off Caps Lock.