I'm sorry you've been having problems with TV go. If you sign into your account via PC/Laptop here, https://virgintvgo.virginmedia.com/en.html. Then go to Settings>Device management you will be able to check what devices you have registered. If you're using multiple web browsers on the same laptop / PC each browser will register as a separate device.
I have two devices registered , my phone and laptop . I cannot remember what browser I used to register my laptop . I have tried logging in on all browsers that I use but this has proved fruitless. It’s very frustrating especially as I cannot re register again for another week or so .