2002 Ford Explorer wheels problems

Purchased a 2002 ford explorer for my 17 yr old daughter. A few weeks later she drove home from college and said she thought it needed an alignment because car vibrating. She had scheduled an appointment to have this done. A couple days later she was driving at 70 MPH on the interstate when her and the passenger heard a loud noise in the back passenger side of the car. The car than began to shake very hard and loose control. She could not keep on the road and rolled across the interstate and into the median.

1. I noticed a humming type sound that would increase as I sped up. I thought I had a wheel out of alignment, or tire off balance. I was due for my 36,000 mile maintenance check, so I took it to the dealership to have everything checked out. They performed a $400.00 maintenance package to my vehicle on may 4, 2004, of which I thought included inspecting tires, wheels, etc.