Mobile app for musician

My company already has a business established, and we are looking to take it to the next level with a mobile app. We are looking for a mobile app that is compatible with both iOS and Android platforms, and can stream audio. We need it to be robust and easy to use, and we are relying on an experienced and professional developer to create this app. We need it to be user-friendly, visually appealing and provide a high quality service. We will require guidance to ensure our mobile app meets our needs and keeps up with the latest trends in technology. Need to sell merchandise and need to upload music which will upload to iTunes, Spotify, YouTube etc. need to have user subscriptions and notifications when a music is uploaded.