Hey there, Wentao Xu
When you had technical problems with the subscription, I would have reached out to your university tutor and to Azure support. The Azure support team could have helped with the technical issue, and you may have gotten an extension from your university tutor, or this may have been taken into consideration when the assignment was been marked.
In terms of the questions, you have regarding the bill you have received. I am going to answer them underneath.
How can I look for somebody telling me where are those 2 invoices from?
From reading your message around clicking onto the link to view the invoice. It sounds as though you have another subscription on another tenant you manage, with your bank & billing information. Please can you follow this link, to see all directories you are connected to here: https://portal.azure.com/#settings/directory
Once you have signed into your account, you can view all directories you are a part of. You will need to click onto 'Switch' to switch to the directory (or directories) you are a member with. Then view the cost management service to check if there are any active subscriptions on the tenants.
My credit card had already been charged, is it possible to get the refund for these 2 invoices?
With regards to refunds, you would need to speak to the Azure billing support. To open a support request, please can you follow this link: https://portal.azure.com/#view/Microsoft_Azure_Support/HelpAndSupportBlade/~/overview
Once you have signed into your account, please can you click onto 'Create a support request' found on the top navigation on the app.
This will open the help and support panel on the right-hand side of your web browser. Please enter a brief description of the issue (I have used "unknown charge"). You will need to select 'Billing', then select a subscription you wish the support request to be connected to.
Once you have done this, it will take you to a support and billing page. Please scroll down to the bottom of this page until you reach a section called 'Need more help?'. On this section, please click onto 'Contact support'
Then click onto 'Create a support request' under the section Help & Support.
You will be able to speak to the support team who can help with billing questions such as this. In the support resources, there is an option to request a refund. However, as you do not know where the charge is coming from, this may not work.
I would like to prevent ALL further invoices, I have nothing to do with Azure in the rest of my life and will never use it again. May I just cancel everything, delete everything, unlink my credit card to prevent ALL future charges? How can I do that?
You will need to work out where these charges are coming from, then cancel the subscription on each tenant. Please let me know if you could see other tenants your account was a member of when you visited the page where you can switch tenants.
Hope this helps,
Nathan