First, verify that you are actually signed up. You cannot tell from looking at your online library account whether you have signed up for text messaging. To find out, text the word NOTICES to email@example.com. A return message will verify whether you are signed up and for what messages.
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If you are signed up, please get in touch using this form. Please submit information about the specific notice you think you should have received, including the title of the item and the date you think you should have received the notice. We will research the issue and reply.