Hello @Marina B ,
welcome to this moderated Azure community forum.
I'm very sorry to hear this situation has occurred.
You reached the community forum where peers helps each other with (technical) questions.
How long do you have the subscription already? How much credits did you spend already? If I look at the website, it says you can only spend 100 dollar of resource credits (including free resources) per year. If these credits are spend earlier, you need to wait for the rest of the year or transfer your subscription to pay-as-you-go.
It seems you need to connect with Customer support again. Because this is a student education subscription, perhaps your university can help?
Regarding starting the IoT Hub again, I'm not sure if Azure resources put on hold are restarted again automatically.
Meanwhile, can you recreate your solution and the resources (including IoT Hub) within the subscription of another student?
If so, you probably need to create new device credentials. If you use a Device Provisioning Service, you need to enroll the device again, to the new IoT Hub.
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