What did you oil? The presser foot or the machine? Try oiling the machine at all the places it needs to be oiled and run a blow dryer on it. If the machine hasn't been used in a long time and hasn't been oiled, things can tighten up.
Or did it work last week and it just started? Then a gear or something else could have broke. Is it a newer machine or an old one? Cheap or expensive. If it's old or expensive, it's worth fixing. New and cheap, it's a throw away.