I've reset your TV Go device list for you and you should be able to re-add your devices back on. Regarding the number of devices, you may register up to 5 devices but only watch on one device. Please see this link for more details.
Thanks for your response, however I did not not sign up to virgin to only be able to watch virgin go on 1 device out of 5. My family watch TV on various devices at the same time. I have been a virgin customer for 3 years if not longer so can you please reinstate watching on multiple devices at the same time. If this is not possible I must request either a bill reduction or I will move supplier.