I'd suggest that you're going to have to provide a lot more details as to the app involved and/or other settings etc. to get any help or resolution with your problem.I hate it!! How can I remove it? I have had no luck... Please help.. thanks
Opps, bad news for the OP, as I just noticed the comment at the link:There are a few things to note with this feature however, leaving a conversation in Messages only works when all of those in the message thread are using iMessage – if it’s a group SMS, say there’s an Android user in the thread as well, you’re out of luck and can’t leave the chat. Keep that in mind if the texts keep popping up.
but iOS 8 and newer versions have a better choice with the ability to leave an iMessage thread.
Can I delete all text messages in iOS 7 Messages? | The iPhone FAQiOS 7 has changed the process of deleting individual and multiple text messages. What if you're interested in deleting everything from the iOS 7 Messages app?
Entire message threads from a contact or group can be deleted from the Messages list. Either swipe from right to left and tap Delete, or touch Edit in the upper left corner. Using Edit provides red circles, which can be used to delete a thread.
At this time, there is no way to delete all messages from iOS 7, unless you restore your device as a new iPhone using iTunes.