Can a rear alignment be fixed on a minivan that has a non adjustable rear?

Took van in for alignment because of high speed wobble and pull. The front was out of alignment slightly and they fixed. Also, balanced the tires which had just been rotated two days ago. Was told the rear alignment was out and could not be fixed b/c it is not adjustable. My van is a 2006 with only 36,000 mi. Does this mean I should get rid of it?