Hi Jaki,
You say you've reset the remote several times but cannot use it for the volume and mute functions, or for changing the TV source.
Check the following actual TV360 settings.
Settings > System > Diagnostics and make sure that the box is connected to the internet. (It might also be worthwhile rebooting both the hub and 360)
Settings > System > One Power and make sure that is switched to ON - you also need to ensure that your actual TV has HDMI-CEC (or it's equivalent) turned on so you can use the source button to cycle between the inputs.
Settings > System > Volume keys control and possibly switch between (your make of) TV and/or (your make of) amplifier/soundbar. It's very easy to accidently have this left on the wrong one which will prevent the 360 remote changing the volume. You press OK on the 360 remote control to switch between the two options, and then press the back button on the remote control to save the setting.
Also try the following to get your 360 remote working agin.
It should work by holding down the 'Live TV' (the one on the right hand side directly below the red power/standby button) and '0' button together for around 10/15 seconds. The Standby button should then start to flash followed by an onscreen message displaying 'Pairing successful - this remote will only work with this Virgin 360 box'.
You can also try the following:-
Put the box into 'Pairing Mode' by pressing the Standby/On button on the front of the 360 box for 10 seconds. Then using the remote control, press and hold the 'Live TV' button and the '0' button together for 10/15 seconds. And fingers crossed hopefully a message should appear on the screen confirming that pairing was successful.