I hesitate to answer this question, as I do NOT sell comics here (or anywhere) and thus I have no dog in this fight.
I also do not wish to derail Rick's thread with a long drawn out discussion on this topic (that can be done in the appropriate forum) for those who have an opinion either way.
To answer your question, however, I believe the issue arises, from rule 14....
Threads may be bumped three times total AND only ONE FULL DAY AFTER falling off of the front page. This does not include "sold" notices, or truly useful informational updates. Note: we CAN tell the difference between a real update and a fake bump-update. Tread that line at your own risk. If you're spam bumping, "lawyering" the rules will not save you. ALSO HIDING YOUR POST AFTER BUMPING WILL NOT SAVE YOU. Yep, we can see that stuff.