Suspension Torsion Bar problems of the 2000 Nissan Xterra

I hit a garden-variety inner-city pothole returning from a day-trip. As a result, the torsion bar on my 2000 Nissan Xterra was broken. Strange, for a vehicle that is marketed as capable of rugged off-road driving. I took the vehicle to the dealership for repair, but my insurance company preferred that I take it somewhere else. Before releasing the car to the other facility, the dealiership said the torsion bar had been ordered and would be delivered the following Wednesday. That was almost 4 weeks ago. Each time I check on the repair, I am told the same thing: part on nationwide backorder---no release date available. It all seems fishy to me. . . Why would the torsion bar be so flimsy on a vehicle supposedly capable of climbing mountains? and why is there such a shortage of this part? are so many needed for repairs that they can't be kept in stock? and what is the holdup on delivery of the part? I've tried to contact Nissan u sa twice, with no reply either time. I feel taken advantage of and jerked around because I'm a woman and I'm at their mercy.