Check for thread jams in the bobbin area too. If you didn't get a manual you can download one at Singerco.com
http://www.singerco.com/support/inst...manuals/search
Definitely do contact the sellers and Ebay, maybe before you make any changes like oiling the machines. If they said they work(work means you can actually sew with it) and they don't then the seller either wasn't truthful or to give them the benefit of the doubt they were damaged in shipping. Either way it's on the seller to make it right.
When I buy something like a sewing machine online it's always with the assumption that it doesn't work and I pay accordingly.
I'm very sorry you got burned and I hope it works out. Please keep us posted.
Rodney