Partner lockout of Microsoft 365 tenant – looking for advice on next steps

Hello all,

I’d appreciate some guidance from the community on a serious situation we are facing.

On 12 September 2025, our Microsoft partner unilaterally locked us out of our Microsoft 365 tenant. They retained exclusive Global Administrator / Partner Delegated Admin rights, which means:

• All staff and directors are unable to access email, Teams, SharePoint/OneDrive, or even log into their Azure AD-authenticated workstations.
• Our corporate and staff personal data is now inaccessible to us as the controller.
• Access restoration has been explicitly conditioned on payment of a disputed invoice (not related to Microsoft licence pass-through).

This raises several concerns:

• Operational: we are effectively paralysed.
• Security/IP: the partner still has exclusive access to proprietary source code and other confidential business data.
• Compliance: we cannot meet our GDPR/UK DPA obligations on availability of personal data while locked out.

We contacted Microsoft Business Conduct on Friday evening with full details of the incident, but so far no human response has been received to those emails.

Questions for the community

1. From a Microsoft tenancy perspective – what’s the fastest/most effective way to remove a partner’s delegated admin access if they refuse to release it voluntarily?
2. Has anyone experienced or seen a similar scenario where access was conditioned on disputed payments?
3. Are there formal Microsoft Partner Code of Conduct provisions that directly address this type of misuse of delegated admin rights?
4. Any practical lessons on balancing the technical fix (regaining control of the tenant) with the legal approach (injunction, regulatory notifications)?

My focus is on regaining secure access, protecting data/IP, and ensuring compliance.

Any experience, insight, or links to Microsoft policy/resources would be greatly appreciated.