I have already read a topic like this in other local here in the forum talking about transferring or sending bitcoin without using the internet https://bitcointalk.org/index.php?topic=5453623.0 it's just a different local language .

       Those who say that you can buy bitcoin via sms may be true that this is really happening, and you will receive a message saying that the Bitcoin you bought has arrived, but if we look at the truth behind transactions like this that in my opinion the confirmation will not be complete until you connect it to the internet, as if the sms is like a ticket or a receipt as proof that you bought a ticket. But once it's connected to the internet, that's when he actually enters.