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When calling some virgin landline from my Vodafone mobile, the receiving end(virgin user) cannot hear me at all.
Have no problems when calling other landlines. Also checked with the virgin landline user when receiving calls from other mobiles network - they can hear them alright.
The virgin landline user have raised the issue with virgin media already and currently investigating their end.
You wouldn't be the same user with a different log in by any chance?
Vodafone are aware of the issue and there should be some response soon.