@Erwin If you are still able to list disk try to delete using the script mentioned in the below article and It may take some time or necessary changes to take place.
Refer to this article and try to delete using the Powershell script
If the issue still persist, we need perform deeper investigation, I would recommend you to contact support, so If you have a support plan, I request you file a support ticket, else please do let us know, we will try and help you get a one-time free technical support. In this case, could you send an email to AzCommunity[at]Microsoft[dot]com referencing this thread as well as your subscription ID. Please mention "ATTN subm" in the subject field. Thank you for your cooperation on this matter and look forward to your reply.
Hope this helps!
Kindly let us know if the above helps or you need further assistance on this issue.
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