[AC Question]

So for some reason, whenever my dad texts my phone, more often than not I receive it as a class 0 message and can't read it- it just opens up as a bunch of unreadable symbols. He believes this might be the work of a virus of some sort from my end.

Is there a way for my phone to be able to read these messages?
Is there a setting I may have changed without noticing that made messages from him arrive as class 0?
Is there a setting I may have changed to even receive class 0 messages at all?
Or is this an issue from his end?

My phone is a Samsung Galaxy S3 Mini, running Android 4.1.2. My dad is the only person I ever receive these class 0 messages from. I don't know what phone he's currently using but I know it's an android.