Having issues with the desktop battlenet app

When I log into the desktop battlenet app, I click on the " Social Tab" within the the desktop app, I take my mouse and move it to the contact list pane " where you see the contacts you have talked to on the left hand side". I right click the “x” to delete everyone who’s names are displayed on the left pane. When I log out of the desktop battlenet app and log back in an hour later, and click on social the people that i have deleted by pressing the “X”, somehow shows back up again. I am not talking about clearing the message content, im talking about the actual pressing the “X” to delete the person name and message all together. I have been dealing with this for a month now.
I have talked to the ingame Gm and was told this should not be happening and for me to leave this so you will know this bug is happening. They have tried everything and nothing is fixing this situation. thank you