Change the language

The app syncing your phone language to the app language

I can't change the language?

Contact Samsung via this app and ask them if it's possible.
If it's not, you may use the web instead of the app.

Yohanan, you are mistaken.
It does depend on the phone's language.

When the phone's language changing,
The app's language is changing.

Weird, my phone in English too, and samsung members app , at English, guess you installed "LocalLang" app

If your phone language is English, it's should be Englisg. If your phone language is Hebrew so the app will be in Hebrew.
If your phone language is English and it's still Hebrew, try to reinstall the app if possible. If it's not possible try to reset to factory setting.