Just take it to an alignment shop and tell them what's going on. Ask them to get you a printout for the rear axle.
Without a doubt you have some negative camber and there really shouldn't be, so the housing is bent I'd suspect. Why it's doing it on both I've no idea. However the printout should give you an idea of what is going on.
camber on the rear axle should be I'd assume ideally within 1/2* of 0* on each side.
You can also try to measure camber yourself with an angle gauge like this one or with even a smartphone app. Inflate the tires to the correct pressure and park on a level surface. It won't be as accurate as an alignment jig, but it can catch the problem if the camber is grossly off.