Thank you for posting this in Microsoft Q&A.
As I understand you have deactivated one of your subscription and you are getting an email stating your data will be removed post September 1st 2024.
You also have multiple other subscriptions.
When you deactivate any of the subscriptions, resources created under that subscription will be deleted post 90 days.
In your scenario if you have any resources which are linked to deactivated subscription then you will have to make sure that you move any of the resources to other subscriptions.
You can refer below article to get more information on moving resources,
Let us know if you have any further questions.
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