Hi @Denis Dixon
Thank you for posting question to Microsoft Q&A.
I understand you're in a frustrating situation where your previous Microsoft 365 Developer Program sandbox has expired, and you're unable to set up a new one using your existing account because the option is no longer visible.
Based on my research, after you delete it, you must wait 60 days before you can obtain a new one.
However, I found another source stating that your subscription could be deleted after 90 days, and your expiration date was over a year ago (January 31, 2024). Therefore, I believe your system may not have been fully deleted, or there could be a misconfiguration within your tenant. 
You can refer via: Microsoft 365 Developer Program FAQ | Microsoft Learn
Additionally, you should use another existing personal account that you have never used to sign up for the Developer Program before, or create a new Microsoft account
As a forum moderator, I do not have the specialized tools or access rights to check your account status or resolve backend provisioning issues related to the Developer Program. In case you still need support related to the E5 program, we recommend contacting Microsoft Developer Support for further assistance. Their support team is best positioned to provide direct help and resolve such issues effectively.
Please note that this is a paid support ticket, which means it requires an active support plan or a one-time support purchase.
I hope you can resolve this issue quickly.
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