Just call in on 150 (VM Phone - free) or 0345 454 1111 (any other phone - national rate) and they will sort it for you. You may be able to do it in your online account but I am not sure.
A VM person will respond here in a few days and can also do that for you on here
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John
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I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired, 1 WiFi, 1 on PA) Hub5 in modem mode with Apple Airport Extreme Router +2 Airport Express's. On 250Mbps, Talk Anytime Phone, x2 Mobile SIM only iPhones.