Hello Ian,
SharedSetService returns only referenceCount in the specified client customer ID only.
Your manager account
(223-833-0176) has shared the negative keyword list to the client customer ID
610-370-7004 and 558-733-1832 as well.
Could you please check those two accounts and remove the association to the negative keyword list first?
Best,
Thanet, AdWords API Team
PS. Your email seems to be unreachable. Could you please check that too?