If the male piece is stuck inside the hole (please, no jokes), you can open the bottom of the amp and take a small eyeglass flathead screwdriver to push it out from the inside. If the female part of the RCA is busted off, you need to replace the whole RCA jack. If it is under warranty, they MAY fix it (don't hold your breath, though). If not, you can find that part at a place which sells electronics parts (or Radio Hack) and replace it yourself. If you have some decent soldering experience, you shouldn't have too much trouble. Just make sure you remove ALL the screws holding the amp board to the heat sink, and all the scews around the jacks.