When I signed up to Virgin Media I was promised a £100 voucher which was also shown on my order summary, I've not received this voucher (I've regularly checked my spam folder, etc.). I subscribed in June so have certainly been signed up long enough to have received this.
As this was included on my order summary I expect it to be honoured.
If you don't mind waiting some more days, then you'll get a response from a member of the Forum Team here. They'd chase up the matter and keep you up to date with the progress of it. Response times are about 1 to 3 days wait. Alternatively ring 150 from a VM phone or 0345 454 1111 from any phone -> Option 1 -> Confirm your details -> Choose from the main menu Option 4 -> Option 1. Once through to an agent ask them to fill in an exception form regarding the unreceived gift.
______ Any opinions expressed by myself are entirely my own and do not represent Virgin Media in any way.
I'm in a similar position, switching to Virgin media in January with the £100 Amazon promotion. I received multiple emails saying it was coming, then a final one in Feb stating I should expect the voucher now, but nothing arrived.
I have also called customer services last week and was assured it was all being sorted, but still nothing.