What do you use to sell ads?
Some services also support dynamic allocation between multiple ad networks. This is useful if you want a higher-paying ad network to serve ads most of the time, and defer to other networks if an ad is not available. Mobclix supports this, as well as the AdWhirl library.
But I understand it is totally your call.
Cheers
It can't be Mobclix, because it's extremely unlikely that he already got October's payment.