TextUs supports automatic opting-out of a Contact with any of the following terms:
Keep in mind these words must be used alone. STOP will automatically opt-out a user but STOP PLEASE will not.
TextUs also allows Contacts to opt-in of their own accord with the following terms:
A user who previously has opted-out can send YES to a TextUs number and the TextUs user will once again be able to message them.
Please note that if you are using a Toll Free number for TextUs, Contacts can only be opted back in by texting UNSTOP.