If it's still under warranty, you can send it back for repair. If a normal RCA cable pulled the plug off the board, the plug's connection to the board was defective.
BTW, this happened to me years ago with a CD player. I opened it up and reinstalled the plug. And learned 2 things: don't use connectors that are super tight, and twist (rotate) the connectors slightly while plugging & unplugging them.