Remote Event Receivers - cannot delete them

Hi

I am able to create remote event receivers during my app development, however I cannot remove them. I have a large number building up as they are added on deploy.

I have tried removing them via REST, Client OM both .NET and JavaScript and none work. I have set the app permissions to maximum (except tenancy) and used an external console both with no luck.

I have office 365 admin, SharePoint tenancy admin, Site collection admin however the error I am getting in all instances is "Access Denied", does anyone have any suggestions why? Or is there a tool I can use to manage them?

Ideally, I would like the code to remove them on retraction or separate utility.

Thanks

SharePoint Dev Guy