Hi,
Thanks for reaching out to Microsoft Q&A.
If you have deleted every resource, then there shouldn't be any billing for sure. I believe the billing you see is for the resources that have been in place before you deleted them, may be taken some time to update the consumption charges. Suggest you reach out to microsoft support for your billing related issues. Support for questions related to billing is free in azure and has been included for all azure customers.
https://azure.microsoft.com/en-us/support/legal/faq/#support-overview
To create a support request...
https://azure.microsoft.com/en-us/support/#get-support
Please Upvote and Accept as answer if the reply was helpful, this will be benefitting the other community members who go through the same issue.