It was just that number, didn’t matter if you selected from contacts or keyed in the number - it would fail. Only way you could call that number was to reply to a relieved call from that number. Anyway - had so many other problems with Virgin coverage and failed connections to Virgin mobile that we gave up and switched to Vodafone - no problems since with calls or coverage.
We live about 1 Mile from ‘Virgin HQ’ in Edinburgh. I’ve had Virgin TV / broadband (Telewest, Blueyonder - as was) for almost 30 years. Went many many years without any issues at all. Last couple years the problems with broadband and wifi in particular have been almost constant. This mobile contract with Virgin was our first go at the mobile service - but too many intermittent problems and call fails for us to stick with it.