Upgrade to paid plan decativated account and it won't let me back in as admin to add payment method

[Robert Smith]

Upgrade to paid plan deactivated the account due to no payment details, and now it won't recognise me as the billing admin to reactivate by adding payment details. Nor will it let me contact Atlassian because it doesn't recognise me as an account admin (even though it still recognises me as the org owner). How do I get back in to the admin/billing section to add payment details and reinstate the account? Thanks.