Loss of steering

try bleeding the power steering pump to make sure there is no air in the system, on my van I had a cage under the engine had to take it off and create a bypass and that solved my prob

Sounds like a pump failure issue. How often does it happen. Perhaps you could ask the dealership to have there shop foreman drive it home or drive it over a weekend. It is hard to diagnose an intermittent problem. I always end up driving customer's cars home. Hyundai as a car manufacturer put a lot of free technical information and workshop manuals on line for Hyundai owners. Check out www.hmaservice.com lots of great information.