cannot open the iphone

Did you see a message similar to the one described here? If you see a message that says 'Your account has been disabled in the App Store and iTunes' https://support.apple.com/en-us/HT208856   "There might be a problem with the payment method that you have on file. ... When you see the message, don't try to edit any of your account information."

You can get Apple telephone support for help in solving your problem using this link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362 

You can also use this iTunes Support form https://support.apple.com/en-euro/itunes-contact. 

And here is how to contact iTunes worldwide support via text or chat using this link https://support.apple.com/choose-country-region/itunes  After choosing your country, see the heading Tell us how we can help.

If your account isn't disabled, do you have access to another WiFi network where you can try? That has worked for several people.

Try a restart.

Restart your iPhone, iPad, or iPod touch https://support.apple.com/en-us/HT201559

Try a forced restart.

Reset Device. https://support.apple.com/en-us/HT201412

If necessary

Hard reset. https://www.wikihow.com/Hard-Reset-an-iPhone

Do a backup and try a factory reset. Then restore from your backup.

Restore to Factory setting. https://support.apple.com/en-us/HT201252

Backup - Restore your device from an iCloud or iTunes backup. https://support.apple.com/en-us/HT204184