O2

HiHaving just joined o2 via the Virginmedia changeover.When I get a voicemail message, my phone message tells me to dial 905, which when I dial it, it is an invalid number.I then have to dial 901 to retrieve the voicemail. One member of the 'o2 commu...

Why is it when I receive a Voicemail, the link on my phone says dial 905. When I do ring 905, it is an invalid number.I then have to ring 901, which is correct to retrieve the Voicemail message.Why does 905 show up on the original message link sent t...