Due to the fact that transactions under £30 are processed “offline” in order to make the donation process as quick as possible, there are circumstances where that transaction is subsequently declined in which case the charity does not receive the funds. This could be because the card has expired or the donor has insufficient funds. This is extremely rare, currently less than 1%.
Please note, any chip and pin transactions taken on the GBx Mini must be done ONLINE i.e connected to WiFi or mobile so any declines for large value transactions can be seen immediately on the device.