Issue:
There's confusion regarding sending text messages in Mexico, as the recipient sees a different number than the one you sent it from. This happens due to a specific regulation in Mexico for mobile text messages.
In Mexico, AT&T is the only mobile company that allows texts to be sent from a regular phone number. These messages are primarily intended for person-to-person, or P2P, conversations. According to the rules, if more than nine texts are sent from the same number in less than two minutes, the system automatically changes the 'Sender ID'—the number from which the message appears to be sent. This is done to comply with Mexico's regulations.
Therefore, if your messages are appearing from a different number, it's due to this regulation being applied. To avoid this, please vote here so we can support shortcode.