Kz1100a3, thanks for your post and sharing what you did to try to resolve this issue. I know it can be frustrating not being able to use important parts of your phone. It sounds like this issue was occurred on one particular night and not a reoccurring issue, correct? Normally our network teams will do testing overnight due to lighter traffic during those hours. You normally won't notice any difference as calls and data will be routed to a nearby cell tower. If there is an issue in your area, the best way to find out is by calling *611 from your cell phone or 800-922-0204 from a landline. Once you enter your mobile number, our system will notify you of any applicable alerts in your area.
If this is something that is continuously happening, it may be an issue in your phone. I suggest resetting your network settings by going to Settings>General>Reset>Reset Network Settings. This step will not delete any data on the phone, but you will need to manually connect and save wifi passwords that were previously saved. Also make sure to update your preferred roaming list by dialing *228 option 2 every 2-3 months.