W610i Headset Connection Problem

I have a W610i and lately I've had some problems with it. It shows that headset is connected to the phone, but actually it's not. The headset logo flashes on and off whenever it wants to. It is very annoying if I am on a call and it suddenly shuts the speaker and mic off from the phone, so I don't hear anything. The problem appeared after I tried listening music with my headset and it had some loose wire inside and I had to twist the wires to hear properly. It is really weird it started to behave like this after that. I have flashed my phone with new firmware and also disassembled the phone and cleaned it really good, but nothing has worked. Also found the 2 pins that if they get connected, show the headset logo. Using a wire I tested and this works like it should, connected shows logo, disconnecting the wire disappears the logo.
Does anyone have any ideas what could be wrong with the phone?