Can’t access phone app without a hard reset at times

Something could have gone wrong during the update process.

I would install a fresh copy of 13.1.2 (the most recent iOS version) using this procedure:

Create a full backup of your device's content, then restore it to factory settings and, in the end, set it up as new, using these steps:--> Restore your iPhone, iPad, or iPod to factory settings - Apple Support

When done, restore your data from the previously made backup:--> Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Regards

Giulio

What model iPhone ?

Is it updated to iOS 13.1.2?

TRy ProustGiulio suggestion.

Otherwise, You can get your device serviced by contacting Apple Support, or by visiting an Apple Store or Apple Authorized Service Provider near you:

Start a service request: http://getsupport.apple.com/

Find an Apple Authorized Service Provider: https://locate.apple.com/

Make an Apple Store appointment: http://www.apple.com/retail/geniusbar/

Contact via phone: https://support.apple.com/HT201232

Contact your carrier: https://support.apple.com/contact

Saifan Pilot wrote:

......

Contact your carrier: https://support.apple.com/contact

Perhaps you need to modify the last line: "Contact Apple Support"

Giulio

Yes, but that sublink drives you to a mere list of carriers and their services.

My opinion is: reading the OP's question, I think it's a matter of software or hardware issue, not related to a carrier service, or plan or billing.

But I might be wrong.

Have a nice day.

Giulio

that link has a link to contact the carriers.