LG FB162 HiFi system that changes function by itself

Hello, I’ve had this LG FB162 Hi-Fi system for a while and I’ve lost the remote. So, I’m only using the touch buttons. One of them, the "function" button, activates by itself while I’m listening to music and continues to stay pressed, as if I had my finger on it and left it there for 15 minutes. As a result, it cycles every 10 seconds from "aux" to "FM" to "AM" to "DVD/CD" to "USB" and back to "aux." You can understand that this is very inconvenient. I’d like to know if there’s a solution or if I’m destined to buy another one.