Hi Vlad Sadovsky
If your invoice is locked and you're unable to create a subscription or pay an old invoice, the best course of action is to contact Azure Support, you can create a support request through the Azure portal. This will allow you to get in touch with the appropriate support team who can assist you with your payment and subscription issues.
For billing and subscription-related issues, please follow these step by step to create a support request:**
- Go to the Azure Portal, click on Help + Support, and then select Create a support request.
- In the Support + Troubleshooting pane on the right, type "Billing" in the search box, select Billing, and then click Next.
2.Select the subscription and click Next. You will be presented with some suggestions to resolve your issue. If none of these apply, please follow the steps below.
Scroll down through the suggestions, and you'll find an option to Contact Support. From there, select Create a support request.
If the solutions appear again, click on 'Return to support request'.
Click Next, and you will then be able to create the billing support ticket.
Hope this helps!
let us know if any help, we will always help as you needed.!
Please do not forget to "Accept the answer” and upvote it wherever the information provided helps you, this can be beneficial to other community members.it would be greatly appreciated and helpful to others.