Does anyone have a problem getting their miles credited?

I've been with AP for years, had no issues getting any eligible fare to credit within a few days, I think ONCE I had to file a claim, that's about it. Then I jumped to SQ, no problems there, everything credited just fine. I've since switched to OZ and had no problems getting my credits there...

I tried crediting some Aeromexico flights to CM, which were eligible...waited, waited, waited...nothing. Filed the claim, they don't even really acknowledge they get it, but there's no recourse other than just filing it again on their site, so i did it again, no dice. I'm waiting for some LH flights to credit to NH, seems like it's taking a rather long time.

Are any of the programs sort of notoriously bad about crediting miles? I currently have between AM/LH/BA (I know I'm talking myself into other airlines/alliances now) like 6 return trips that haven't been credited anywhere, despite my efforts, and don't wanna just lose them cuz that's a waste.