Peugeot 307 Radio Problem

I will tell you about a very different malfunction. I gave my vehicle to 10,000 maintenance. After the maintenance process was over, I bought the vehicle and after a while, my radio stopped playing and I didn't see anything about the radio from the trip computer and it was not controlled by the keys on it in any way. I brought it in front of it, got out after a while, got out again in the car, the radio started to play, but there was a constant beep beep. I turned the ignition off, I turned it on again, there is no reaction on the radio, it continues like a vicious circle. Because it's gone, but they couldn't see any problem and they said that your radio was broken and cut it off. I'm very confused if it's broken, why should it beep once in a while?