Help with 2012 radio

[Chrisd3179]

i have a 2012 ds3 with an aftermarket stereo, while the car was in for service they disconnected the battery and now the display with time etc at the top centre of the dash, is now just flashing with old dates etc and I’m unable to reset it

is there a way or do I need to put an original stereo in? If so which one and can I get one to fit with Bluetooth?

Thanks for any help