Hi @Tommaso
Since your issue is related to the billing/costs I would recommend to contact Azure Billing team, Billing related tickets are free.
https://azure.microsoft.com/en-us/support/create-ticket/
Check usage of free services included with your Azure free account
You're not charged for services included for free with your Azure free account, unless you exceed the limits of the services. To remain in the limits, you can use the Azure portal to track the free service usage.
refer- https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/check-free-service-usage
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