Duplicate text messages

[nelag2002]

Apparently some texts that I have sent now send multiple times to people.  What is worse, when i try to send them a new text, an old text will send instead.  So for instance, if I say "How are you?"; They say "Fine" and then I say "Glad to hear it" instead of the last "glad to hear it" they will instead get my "How are you?" text message again.  Please help!