If ya used ****part bushes take one of the springs off and remove the bush and shackle, assemble the bush and shackle outside the spring and place the shackle into a vice, torque it up to the required poundage then grab a set of gas pump pliers or stilsons and I think you'll find the outer casing of the bush spins on the rubber bush. Had this myself recently and found this to be the problem.
Bought 2 lots of these recently from ****part and they've all been the same, Return them to where you bought them from they'll be happy to exchange or refund you for them. I've ended up buying the genuine ones. a couple of suppliers are already aware of this problem as I've emailed a couple of them.
If you look at the bushes themselves on the ends they are not rolled over the rubber which pinches and prevents them from slipping, you'll never be able to set them.