The data is probably fine, I'm confident you'll be able to get it back if you're willing to pay for it. It sounds like it's just a bad controller, which wouldn't affect the disks -- it just stops you from accessing them. If you feel like tinkering, you can get an equivalent drive and replace the controller, but that's not guaranteed to work, and you do risk damaging the data by opening the drive, because the platters are very delicate and sensitive to dust, etc.