Hello! I'm sorry to hear that you're experiencing issues with your WiFi. If you purchased a lifetime subscription for your WiFi service, it should not have become unregistered suddenly.
Here are a few things you can do to troubleshoot the issue:
1. Contact the customer support of your WiFi service provider to inquire about the unregistered status of your device.
2. Check if your WiFi service provider has recently updated their terms and conditions, as this may affect their policy regarding lifetime subscription.
3. Restart the WiFi device and check if it has been properly activated.
4. If none of the above steps work, you may need to consider purchasing a new WiFi device or upgrading your subscription plan.
I hope this helps!