Service users were affected by the glitch which appeared to affect the network for calls placed on Monday evening only notifying phone owners the next day.
Mike Fawkner Corbett, Head of Consumer at Sure said:
“Due to a technical issue some customers have received delayed notifications for voicemails and missed calls this morning (Tuesday 23 April).
“The issue has now been resolved and we apologise for any confusion or inconvenience this has caused.”
A Facebook post from the company received more than 100 comments: