I've recvd equipments that were tested
prior to shipment and they arrived wet but clean. Perhaps EM tested the pump a while ago and it was sitting w some water that became moldy/dirty? Can OP perhaps ask EM this question (when were the pumps tested) since EM insists the pump is new, so in the future we can all avoid experiencing such an incident?
The OP happened to take the new replacement pump apart and noticed the equipment was dirty/used looking so became suspicious. Why are we blaming the customer for catching something amiss & having to defend his frustration?... Talk about blaming the victim at a trial.