Are you blaming this problem on what some unlucky person did three weeks ago??? That's quite a stretch. BMW is by far one of the least customer-friendly manufacturers. They are too selfish to even release their service information and paint codes to the independent repair industry. They for sure are not going to allow us to buy radio service manuals. You are tied to the dealer when the radio has a problem. Other than checking for blown fuses, there is nothing anyone else is going to be able to do.