IPhone 5SE is blocking numbers and I am not doing it

*HELP*

My mother's phone is blocking everyone's number.

Please note:

I have reset the phone back to factory twice.

It still keeps on happening.

Please note:

The do not disturb is not on

I have an understanding of Apple products.

This has never happened before and I need help

Please note the Apple store/G Bar is an hour away

Any other suggestions?