My guess, concerning your problem (uncontrolled spin), would be severely uneven lines, or as Scott mentioned, a bottom (brake) line snagged on the bungee, at the bottom of the vertical spar........ Been there, done that !
It's very important that the right & left (top) lines be equal. Also important that the right & left (bottom) lines be equal. Normal flying will create slight differences, in the top set of lines vs the bottom set, but this is easily compensated for, with your knotted leaders. However, it's very important that right & left lines be matched up equally, whether comparing the tops, or the bottoms.
Oh, and just because you have new lines, don't just assume that they are perfectly matched. I've seen new lines that were mismatched, by as much as 6 inches.
Based on the description of your day, and based on the fact that you were able to go straight up, and back down, some of the time, I'd guess that you had a wrap, as described by Scott, above, when you went into the uncontrollable spirals. (just my opinion)
This is also where you can pop a leading edge - when that spiraling Rev meets the ground