We appreciate that this can be very frustrating but it should be rectified as soon as your group member(s) complete their next session.
As the Facility Fee is deducted before members are credited with the session amount, it enables the in-place routines (links on the transfer page) to fix any negative balance problems. In some cases, however, the in-place routines cannot deal with a member's negative balance. This would be when a member's most recent transaction is a spend or is not available for withdrawal, see the date next to each transaction on that member’s Credits History and you see a message saying:
[amount] credits could not be removed from [members name] Credits Account because they have not received credits in corresponding quantities. Click the '+' icon next to [members name] below and deselect transactions to the value of [amount] credits and then submit.
In such cases, you can still transfer if you follow the instructions within that message. Alternatively, as a Group Manager, you can choose to exclude those affected members from the Group transfer altogether and proceed with the transfer for the rest of the Group.
This Help Centre Article explains how and why negative balances occur for your members.