In Brazil, people get so much SMS spam and phone call spam that many people turn off notifications for all text messages and phone calls and use only Whatsapp (even for voice calls).

But once in a while my iPhone in Brazil will get spam as a unblockable "system message". I'm not sure if I'm using the correct term. I'm mean that it looks just like an Apple system notification and it disappears without a trace afterward, but the content is obviously spam.

I wonder how they are able to do this.