The knee-jerk reaction here is to side with OP, simply because the actions of Quickseller/ACCTSeller are shady.
But Quickseller's questionable ethics and being (likely) driven by vindictiveness do nothing to invalidate his claims re. OP scamming TF, those are factual, and could easily be verified here:
https://bitcointalk.org/index.php?topic=303613.0TradeFortress himself (most likely) being a scammer is neither here nor there - thieves get robbed too. And 2+2 still equals 4, even when said by a liar.