My heart breaks for you with all the work you put into it. You have to try your best to get the threads clipped and get it into some sort of flatness so it can be quilted. Don't give up. I spent over an hour trying to undo a mess of yarn for this friend. Someone had dropped of bags of yarns at the Senior Center. It takes a lot of patient and I only had to cut the yarn once. I find when I have a problem with a quilt, I will work on it for 15 minutes, then walk away and do a household chore and then come back to it refreshed and work on in for a bit more. Hopefully, it will make the task easier to get it done especially with the deadline looming.