Welcome to the Community Forum and thanks for your post. I'm sorry to hear that you are experiencing a problem with getting your Cubot Dinosaur working on your Virgin Mobile 4G connection. Does the 4G connection work if you put your SIM card into a different handset?
If this issue is specific to the Cubot Dinosaur, please contact the vendor you purchased the phone from, or alternatively, get in touch with Cubot direct on http://www.cubot.net/support/.
Please let me know how this goes.
Virgin Media Forum Team
Need help changing SIM card? Find out more about activating your 4G ready SIM. 4G SIM Swap Help