How to delete SLA and it's linked SLA Items

Hi all

So I'm trying to delete a SLA and recreate it but Dynamics won't allow me to delete it. 

The SLA itself is deactivated and not being used. I tried deleting the SLA items as well but it throws the same error which provides no information. Any ideas on how to delete SLAs? Is there a order that I need to delete by?

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