Can I come into the apple store and get a tech person to restore my iPhone?
I need help in resetting my iPhone 6 to factory settings
Earlier iPhone models
Do the instructions in this guide published by Apple 👉 How to factory reset your iPhone, iPad, or iPod touch - Apple Support work for you to restore your iPhone to factory settings?
Not sure whether the Apple Store can help you out, however I encourage you to try if the action listed in the link above, does not work.
Axel F.