Did not use it until now (but am going to...).

Do I understood right?
It is about the addressbook not showing the contacts? Or not showing the current status of IM partners (away, offline,...)

Either way I would go with a
killall osso-addressbook
or
kill `pgrep /usr/bin/osso-addressbook`
Try this first, then:

What also may be needed is to "restart" the telepathy processes
like
~# ps |grep telepathy
1278 user 4688 S /usr/lib/telepathy/telepathy-ring
2331 user 16892 S /usr/lib/telepathy/telepathy-haze
2334 user 7472 S /usr/lib/telepathy/telepathy-sofiasip

afaik:
sofiasip is for sip/voip accounts, haze (and others) for IM.
Output may look different depending on installed extensions.
You may go one by one (preferred, pls post back result) with a
killall telepathy-...
or all together
kill `pgrep telepathy-*`
kill `pgrep -f