Maybe this is what happen to you @op, i know am a newbie here but i have take my time to go through the forum rules and payment process and i also read some where that new acct must make up to 50 post before getting paid, since you aren't newbie you should get paid,
Also i read that this payperpost campaign will last for a long time, so most definitely they are still paying, so i think maybe it was a bug that course it, just continue posting i guess.