The transaction log for database is full due to 'OLDEST_PAGE'
This is not something you should ever see on an Azure SQL Database.  You should engage support on this.  

There are a couple things you could do yourself, if you want.  First just try to CHECKPOINT the database.  Second if you are sure you have no active transactions, change the database SLO.  Taking it out of the Elastic Pool, then putting it back in.