2000 Pontiac Sunfire - Trac light, speedometer, etc.

Hey, I took the car to get its oil changed yesterday and it was working fine. When I got it back, the traction light was constantly on, the speedometer wasn't working, and when you'd press the gas pedal the engine would rev, but the car would take a few seconds to actually accelerate.

I took it back, they said whatever it was, wasn't their fault.

The car has 90,000 miles on it, no leaks, and the only problem is a slight whistling when driving too fast.

Any thoughts?