Looking for suggestions on how to fix 
fixing is nigh on impossible. You can try bending it back but it may well snap, annealing of the material would be possible to avoid this, but the ally would then need re-heat treating. This is the peril of Al frames, steel or Ti in this condition could be fixed easily. If it’s too bad get a new one, if it’s bearable then stick with it.
Heat it with a torch before you bend it back
The trouble here is that it is a relatively brittle alloy, and is already cracking internally from the original bend. It’s weaker now. If you bend it back cold, it is likely to snap.
Heating it will allow it to bend back without damage. But how strong will it be ?
If you do decide to heat it, don’t bend it hot. Apply liquid soap to the metal and heat with a gas torch until the soap is well burnt. Allow it to cool slowly (don’t dunk it in water) and then do your bending.
Rather than try to bend the frame back, wouldn’t you be better of trying to bend a sacrificial seat post the opposite way? A steel seat post will bend ok, and even if it does all go wrong, you haven’t exactly lost out a lot.
Either that, or wear platform shoes on one foot to compensate 
STM
bend back and weld?
I like that idea, and may end up employing it in the future.
Don’t KH frames have warranty?
yeah i think they have a warranty. and unisykolist, its an aluminium frame. its possible to cut it off, clean it up and re-weld it, but aluminium welding is hard, and a skilled job.
this would be possible if you rabricated a new stem for the frame, but would be extremley unlikely to retain its original strength. Depending on how old it is, and what you did to bend it, it might be worht questioning if it can be replaced under warranty.