CX flights generally seem to post every Tuesday with the cut-off for the flight being flown sometime the previous Friday. This makes the posting time average from 4 days to 10 days. So, for example, if one flies CX on a Saturday the flight will not normally post until the following Tuesday (10 days later). This has been my experience, but YMMV. Unfortunately, I do not think missing credit requests would conform to this Tuesday rule - but they might. The best bet would be to wait the 28 days before following up again.

-FlyerBeek