Uninstalled my whatsapp & non-stop error message

[Note_II]

An hour ago, I activated my sim card and inserted into my phone. Right after I turned on my phone, I notice my whatsapp on my home screen disappeared and few seconds later the error message of "Unfortunately the process com.android.has has stopped" keep popping up on the screen. Everytime I click to get rid of the error message, it pops up again in 2 seconds and the cycle continues. I cannot swipe to another screen within having to click to get rid of the error message.

Meanwhile, I keep receiving identical sms with my pin (about 8 of them). Took out the sim card, no more sms of pin but the error message is still there.
 
I searched through the forum and found no such topic. I don't know what Public mobile's sim card did to my phone and needless to say I am not a happy camper right now.
 
Not to mention I paid for the plan already and I can't use it. 
 
If anyone has similar experience or solution (tried the ones on google already and error message stlll pop up), please share. 
 
Public Mobile team, please contact me immediately to resolve this. I have no idea how your sim card can uninstall my whatsapp and created this error message. 

[Note_II]

It happened right after I inserted the sim card. This caused it.  

[Someone_here]

I agree with @computergeek541, I don't think iyour problem is related with Public Mobile, even if the timing suggests it. My best bet would be to keep looking for solutions on the Internet and in forums, and ultimately, if no solutions are found, go ahead with a factory reset...

If you plug your phone in your computer can you back up your data?

EDIT: Have you tried this (clearing the SIM toolkit cahce)? http://thedroidguy.com/2017/03/how-to-fix-unfortunately-the-process-com-android-phone-has-stopped-90...

[Note_II]

This literally happened right after I inserted the sim card and turned on the phone. 

The error message then appear and whatsapp and google play store icon are couple things I notice are missing. 

[computergeek541]

In my opinion, there's a strong possibility this has nothing to do with your sim card.  A sim card can't uninstall an app. 

Smartphones are just like computers, and sometimes strange things happen.  I once had an HTC phones that started crashing every time I opened the messaging application.  Nothing would fix the issue unless I did a factory reset.  To this day, I never did figure out what caused that, nor did it ever repeat.