I followed your instructions of disabling all other messaging apps but this did not fix the issue. I do not receive any messages from some of my contacts but receive messages from others without issues (no apparent pattern). I dont get notification of messages nor does the conversation go to the top of the list. However, when searching for my contact's name and opening the conversation, I am able to see messages. Please let me know what is causing this. Im using a Galaxy S6 edge.