@serge resplendino To delete a subscription, select All services, then User subscriptions, to display a list of all subscriptions on the system. If you're working on an offer, you can also select Subscriptions from there.
Note: Deleting a subscription also deletes any data and resources it contains.
For more information: Please refer to this article Delete quotas, plans, offers, and subscriptions
If you still find any difficulties in canceling the subscription, for more specialized assistance on this kindly contact Azure Billing/Subscription support, it's free, and it's the best choice for you.
Hope this helps! Kindly let us know if the above helps or you need further assistance on this issue.
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