Failure to delete service providers

It says that all I have to do is remove the services offered by a particular provider, and that will remove the provider from the list. This isn't working.

I have more service providers in the list than I do actual people now, because when attempting to remove service providers, the system ignores me, and sometimes even adds another to the list for what appears to be no reason at all.

Basically it is preventing me from removing service providers. When I try and remove them all, it leaves me with 4. When I set the remaining 4 to the 4 individual people I want and hit save, I'm left with 8.