We can certainly get our IT team to take a look at this issue for you. Before we do this, we will need to ask if you have tried the following first.
Try a different password. Certain things are too guessable to be allowed. No special characters, only letters and numbers, MUST begin with a letter, try keeping it between 8-10 characters. Try something like part of their address and part of postcode (ie, Gardens3HY).
Please try the above first, can you also try another web browser, clear all cookies/caches and history too. We also ask you to try a different device and try to register on our Virgin Media app.