Microsoft Azure Backups not reducing available recovery points or destination usage after retention period has been reduced.

Microsoft Azure Backups not reducing available recovery points or destination usage after retention period has been reduced.  

I had the retention period set to 30 day with around 6.8TB of backups. Over a week ago I changed the retention period down to 7 days, and it took a couple of days for the total recovery points to go down to 7. The destination usage was still going up.   

I have come in today (monday) and the total backups is now 10 and the destination usage is now 7.57TB.  

I only have the one server backing up to Azure Backups Services.  

My questions are;  
1. how long does it take for azure to delete backups from outside the retention period*   
2. why are there move recovery points that the retention period?  
3. Is there a way to purge just the backups outside the retention period?  

*It does say the backup agent, "space allocation data is updated on a daily basis".

It would be a great help if anyone had some information on this as the storage costs are getting very high.

Thanks for the help in advance

Z