No, a disconnect did not happen while I was in the middle of the trade that I'm aware of. But it's been my experience too that a disconnect is not always apparent at the instant the disconnect happens, so I'm not entirely sure whether or not I was disconnected at the time of the trade itself. If I was disconnected wouldn't the ring have reappeared back in my inventory when I signed back on?
I've already completed the other quest, was given the gold ring, and thought I had delivered it to the person who had requested it. Does this mean that I will not be able to complete the "Gold Ring" quest? Now the person who had requested the ring refuses even to talk to me, just tells me he is too busy.