Samsung on max mobile running app then no display

[HITESHR]

On running mobile when I use whatup then mobile hang and no display showing only black screen 

I can't switch on the phone and not showing charging 

Need help to resolve the issue @samsungindia

[cs-member11]

Dear Samsung Member,

Greetings from Samsung Customer Support!

We acknowledge your query and apologize for the same. Please perform the below mentioned steps to resolve the issue:

* Check app cache: Clear cache memory of a particular application: Setting >Apps >Now pick the app. For example 'Samsung Internet' >Storage >Clear Cache.

For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application>Support>Type your query>Ask a question/Tap an error report>Send)

Thank you for writing to Samsung.

Warm Regards,
Samsung Customer Support

[HITESHR]

Mobile not switching on
How can I do these things???