You can block unwanted messages by sending a free SMS to 88444 with the following details:
• Send the word “Block” followed by a space and then include the sender’s number/ID.
• e.g. To block unsolicited messages from sender c12aB: Send “Block” space c12aBC to 88444
You can block messages from up to 5 senders in one SMS by mentioning the senders’ IDs/ numbers separated by commas.
You can unblock messages from previously "blocked" senders by sending "unblock" followed by a space then the sender's ID/number to 88444.