Have got the same problem in C code.
osso_abook_aggregator_get_master_contact_count always gives me 0, osso_abook_aggregator_list_master_contacts returns an empty list, etc.

So maybe your problem is not caused by python or ctype.

Could you give links to C code you've seen ? (I can't find any working C sample for getting a list of contacts)

Edit: working C code example here http://pastebin.com/BfvS2wC0. Should be easy to do the same with ctype.