Why did the caller get the text message?

This situation is likely to be a problem with your own mobile phone settings. If you want to know whether this is the case, you can refer to the steps:

First, open the phone "Settings" and then click "Phone", and then enter the incoming call settings to see if the incoming call is set as a message forwarding reminder, because the settings of each phone are different, but most of them will enter the "Phone" setting option from the "Settings" option. If the message forwarding reminder has been set, just turn it off.