Hi,
First thing is you are responsible for backing up your databases, so you can use automated export feature or can use copy database command o back up your dbs periodically.
In case is you loose backups and main db gets deleted by mistake you can open ticket with Microsoft but it does not mean that you will get your data for sure or not.
So never rely on Azure platform to backup your data, it does provide high availability as it maintains multiple replicas.
Thanks, Dilkush Patel Microsoft SQL Developer Support Microsoft Corporation