Hi Harry Booth
You may have used services that are not included in the free tier. When you sign up for an Azure free account, you receive a limited quantity of free services for 12 months. Any usage beyond these limits or any non-free services will result in charges.
To better understand the charges, I recommend checking your service usage in the Azure portal. This will allow you to identify which specific services may have caused the charges. If you're looking to avoid further costs, you can delete any resources that you no longer need.
https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/avoid-charges-free-account
https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/cancel-azure-subscription#final-charges-and-last-bill
You can actually receive free support for billing-related issues, as billing tickets are free of charge
To create a ticket, go to https://azure.microsoft.com/en-us/support/create-ticketto create an incident and select Billing
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