For this, we would suggest you to have a word with the nearest dealership as they will be the better person to assist you because the MG has not revealed the complete details about the music system brand. You can click on the following link to see the details of the nearest dealership and selecting your city accordingly - Car Showrooms.
For the service charges and annual maintenance cost, we'd suggest you to get in touch with the nearest authorized service center in your city. Follow the link and select your our city accordingly for [service centers@https://www.cardekho.com/MG/car-service-center.htm