2002 Chrysler PT Cruiser radio going crazy

My radio just stopped working except the face light or power stayed on even with the key off. I disconnected the batt. & When I reconnected it, it works fine but I take it to the dealer anyway. They said maybe a fluke & maybe it will never happen again, but said if we keep it, we will fool around for a few days to see what it is. I said no. A week later the radio didn't work at all. I disconnect the battery and re-connect & and it works. So yesterday when I went to change the channel, it just went dead except for the power, faceplate still lit. So I disconnect the battery again and this AM its fine, but I didnt touch it and on the way home, I know what station it was on but the #'s started changing all by themselves?