Yes, that sums up the situation. You could always try to get a refund from the seller on safety grounds, maybe referencing this thread.
I don't know what voltage and current you need, but yes, ebay second hand genuine brand name laptop adapters (eg, Dell, Lenovo, HP), as opposed to the new "for xxx model" clone ones, are an excellent and usually cheap purchase. They are engineered and tested to meet very strict EMC and Safety approvals.