are you on p.a.y.g or contract – is your account upto date?
Was your phone working fine recently? (I.E it’s not been unregistered due to inactivity - If you are on pay as you go and you haven't made a chargeable call within the last 90 days. This is the most likely reason for "Registration Failed").
If this is the case, you'll need to call Virgin mobile customer services on 789 from another Virgin mobile or 0345 6000 789 from any other phone so they can look into it for you.
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