If the 360 remote isn't working with the box then try resetting and repairing the remote to the box,
Press and hold the TV and 0 button for 10 seconds - this should force pairing,
If that doesn't work you could try,
Pressing and holding the TV and Rewind button for 10 seconds which will factory reset the 360 remote.
After the factory reset, press and hold TV and 0 button for 10 seconds and it should now force pairing.
If it's the new version of the 360 remote it maybe 5 seconds instead of 10 seconds but basically the light on the box should flash when paired, if it's the newer remote then it will only have 2 batteries, you could also try removing the batteries from the remote to reset it.