All MATE international roaming packs have a 7-day validity period. Your pack starts upon activation — either immediately when you purchase it, or on your chosen start date if you scheduled it in advance. It expires at midnight Sydney time (AEST or AEDT) at the end of the 7th day, regardless of which country you’re in.
For example, if you’re in London, midnight Sydney time is around 1:00–2:00 PM local time, depending on the time of year.
Any unused data from your roaming pack can’t be rolled over, refunded, or transferred to another pack. Once your pack expires, you can simply purchase a new one if you need more data.