Ebay scheme alltechwholesale (bad esn)?

I recently purchased on eBay a Palm Pre Plus from a seller named "alltechwholesale". Later I messaged the seller if the ESN is clear or not and they said "We are unable access the ESN number" I read a few bad reviews about people recieving phones with bad ESNs from this seller and I am curious to know any more bad experiences. Are these people criminals? The product is scheduled to be here Monday and if there are many bad reviews I will send it back because I know even if the ESN is clear there is something else bad with it. So please tell me about your reviews. Also, WHAT CAN I DO TO CLEAR THE ESN IF IT IS BAD?