Are you trying to rotate your highbacks parallel to board edge? If so, dont. Flow's arent great at that.
This is one of the downsides of the H and M frames. The new Fuse frame for next year is much simpler to adjust.
I had this issue myself with my M9SE's. It will go back into place right, just try and fidgit with the way the highback is sitting in the frame and the way the arms are lining up with the bolt.
However, if you arent even getting the lock washers teeth to engage the track on the frame, you may have cross threaded the bolt. If so email Flow or find a dealer and they'll get it figured out.
If nothing works, take it to where you bought them and make them do it.
That thing I do to escape the world and have fun with my friend