Oh I feel your pain... had EXACTLY the same thing happen to my Tangerine Dream grow... I actually thought about ripping the top of the tent off!
What I DID do was as much LST as I could find to do... if the stems are pliable - and I stress PLIABLE - you can bend them down to at most a 90-degree angle ... hell, I think I even did some "Z" shaped LST on mine! If you're growing in fabric pots, take a LONG strip of some soft cloth, loop it over the stem you're trying to pull down and gently pull as much as you can - do it slowly so you can judge whether there's resistance there or not and stop when you feel serious resistance - and then pin or otherwise attach the strip to the pot. I bought some LST clips that I also used WAY up high and well away from the main branch because that's where the stems are going to be the woodiest and easiest to break... From there, I had to do a lot of defoliation to keep light on the underneath buds... Check out my diary if you want for some pics of what I had to do. I was growing 2 plants and ended up having to get a second tent so they could each have their own... it was wild...
Good luck to you!