Hi lazyOwl,
We appreciate you reaching out to us.
Based on the details you've provided, it sounds like you've already performed some steps to troubleshoot the issue. However, since we do not have details as to what steps you've already performed, we'd like to share some troubleshooting steps just to make sure we didn't miss any.
If you haven't, please check for a software update and make sure that you are running the latest version of iOS.
Making sure that your device is up to date is a great step to correct software-related issues
Kindly secure a backup and update.
How to back up your iPhone, iPad, and iPod touch - Apple Support
Update your iPhone or iPad - Apple Support
Next, please check for any carrier updates.
The article below may help.
Manually update your carrier settings on your iPhone or iPad - Apple Support
If the issue is not software-related, it is possible that the issue is hardware-related.
If you have already taken the device at an Apple Store or Apple Authorized Service Provider, and a technician informed you that the issue is not hardware-related, we recommend that you continue working with your carrier.
These set of steps are designed to isolate the issue.
Take care!
