Can inactive a contact that has a user accout and is on more than one supplier record

We have a contact that is on more than one supplier record that we can not remove.  We get an error message that hz_org_contacts record is locked.  Since we know that is not actually the case, we need to determine what we are doing wrong so we can inactive it.  The attached screen shots show in detail the error and how we got this message.  I was able to do this in a test environment by going in the back end and inactivating them but I should not have do to that.  Any help that can be provided would be