Did you use Enterprise or Business? Enterprise does not assign the CloudPC without doing some set up work. Business should be visible immediately in https://windows365.microsoft.com. Both should be visible in the license overview in the admin center (https://admin.microsoft.com) if you have the right role to see that (global admin should do it :)
If you see the license, you got the license and it will be hard to get a refund. If it is not there then you got an invoice but no service and you should use the contact information on your invoice to get a refund, either way, you should start a support case to get any refund.
