I've just received my S3 back after a repair. They sent it back with a faulty charging cable but I have a spare, so wasn't too bothered about that.
Problem is that it looks like they replaced the innards with parts from a used phone which is locked to another network. The phone asks me for a SIM unlock PIN and won't connect to VM. 150 couldn't help and passed me to tech support. They couldn't help and have to speak to the repair centre tomorrow.
This is my second contract with VM - the first one was a Blackberry and they sent me a faulty one of those back after a repair too. I shall not be entering into a third.
Get out when you can Chriscop, they are worse than useless. Just proves Virgin DO send out faulty mobiles despite their insistence they don't. I've had 2 now, both Galaxy's like you, but mine were the S4 mini. First one they lost/destroyed, second one they've used the 'liquid damage' ploy. 6 weeks now without a phone. Do Virgin care, **bleep** no. Good luck with getting yours sorted.