Thanks for your post and welcome to our community.
Really sorry that you're having an issue with the new SIM cards and your current phone, this isn't good.
I have tried to find your account using the details you joined the community with but sadly I've been unable to do so.
If the SIM isn't valid with your current handset then we would try and provide an unlocking code to resolve this, in the case that doesn't work then we'd be able to discuss a more personalized resolution with you directly.
Has this been resolved since your post?
If not then please let us know and we can discuss it further via a personal message.
First, thanks for responding. No the mobile isn't working I have tried various times with the new sim over a period of weeks, the phone now appears useless. It would appear that others are having the same problem with no solution. I have credit left on the phone but cannot use it will this credit be refunded? As I need a mobile and Virgin have no shops open and are practically impossible to contact I have moved providers. I am totally disgusted with Virgin.