You can contact VM to report the problem using ...
Text service on 07533051809
150 from Virgin landline.
0345 454 1111 from any other UK phone.
The best time to call is weekdays 08:00 to get a UK agent, anything after 10:00 you must realise that you are quite likely to get through to an offshore agent that doesn't speak English as a first language.
Or you can wait on here for one of the VM Staff to pick up the thread but this may take a few days.
Thanks so much for your first post on the forums, welcome to the community! Apologies for our delayed response and to hear that your booster has stopped working.
I have been able to locate your account and can see that you were able to speak with our faults team who arranged for some replacement boosters to be sent out to you. We'd love for you to let us know once you've received them so we know that the new ones are working OK for you.
If you need anything else in the meantime please don't hesitate to get back in touch by adding to this thread.