Check that all cables are fixed in to TV, Box and HUB .
A reboot of your box and TV can fix these type of trouble at time.
If you are using a sound bar or other sound systems a reboot and if using Bluetooth for link it may help to link by cable if you keep having sound troubles as other signals can give troubles when linked by Bluetooth.
check VM channels to see if they are giving same sound troubles if after a reboot and cable check then phone VM.
I'm sorry to hear about the problems you're experiencing with your TV service lately, how have you get your audio set up for your TV service at the moment? Are you using a surround sound or is your audio going through the HDMI cable to the TV?
I've been able to locate your account to run some tests on the set top box from our end too, we're detecting some parts of your box as offline at the moment, which could be causing these problems. Are you having trouble with your On Demand or any other applications?
How long has this been happening for? If this is something that continued to occur I'd like to request we take a closer look so get in touch if that's the case.
Apologies again for the inconvenience caused, we'll talk soon