Trying To Delete A Messenger Group Without Messenger Completely Shutting Down?

on several occasions i've deleted a "group" from my messenger the problem comes after i do so. i would right click on the name of the group to delete, after all persons are off that "group". once the "group" is gone my messenger will cause a send report or don't send report notice. then the messenger completely shuts down. when i restart the "deleted group" reappears!