Hi Barnaby Davies,
The support team should be able to assist you with any issues related to your account and credits.
Please open a support ticket with the Founders Hub support team by following these steps: https://foundershub.startups.microsoft.com/signup?drawer_open=truePlease click on "Support" on this page to submit support ticket.
If you have already contacted the support team, we would appreciate it if you could kindly share the support ticket number with us. This will allow us to review your request internally and assist you more effectively in resolving the issue.
Please refer: Founders Hub Portal
Thank you.