is this poor reception usual at your home address or a recent thing?
Try entering your postcode into the EE service checker (Virgin Mobile works on their network) to see if there are any known issues.
If that shows as OK, perhaps give Virgin Mobile customer services a call (freephone 789 from your Virgin mobile) or 0345 6000 789 from any other phone (standard rate call or included in any minutes) so that they can look into this further for you.
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