How to clear your Massages i select them go to bottom does not have delete. shows up for selecting

I just got done doing this I was way over my allowed messages since my gold membership ended. On the mobile version you have to click the boxes to the right of each message then go the the top where it says "selected" click that then scroll to the bottom where the tab pops up and scroll thru the options to find "leave conversation" I just deleted about 8 pages worth so I can accept and send pm!