Lost access to Azure portal (MSDN Sub) after upgrading to new Phone. (MFA restore failed)

Gone around the houses trying to get support for this one so asking here. I have the MSDN sub, which includes Azure. I have an Azure sub set up attached to my personal (@outlook) email address.

I recently upgraded my phone, but as part of the restore from backup, despite all other MFA working. The MFA for the .onmicrosoft.com account tied to the Azure portal failed. This has meant that I cant get access at all to that Azure sub because there is no way around the MFA prompt. I cant raise support tickets, because i'm prompted for MFA.

Is there any way I can either get the MFA reset, or even as a nuclear option (Less preferred option) the Azure account trashed so I can set up a new one.