Hello, dear JohnCooper
We would recommend that you check the syntax of the SMS commands that you send.
It may be better to contact your device manufacturer or dealer with such a question, as they can provide the necessary instructions.
In any case, write to us to firstname.lastname@example.org and send us your username, password, photo of your tracker, manual (if you have one), as well as screenshots of SMS commands and the device’s responses to them. We will check additionally.