The ticket has been escalated within our upstream provider's network team. We have identified that mainly Spark people calling in are are impacted where the B side (you) are unable to hear the A side (spark) phone call. We are also noticing this with some Vodafone callers. As a work around, if a caller ID is presented, you can redial the number and talk as normal until the issue is fixed. We will be following the issue up within the next hour. Any further updates will be available at https://www.neos.co.nz/status