Yes, I did! It was a 50x 50 quilt that the quilter left a pleat in the backing? There was no living with it.
You have my best wishes. It's seems overwhelming but work in small blocks of time. Just a suggestion to rip from the backing side. The batting will protect the actual quilt. The backing was toast and went in the trash asap. I didn't want reminders.
I used one of the curved knife cutters and worked on one stitch at a time.
Again, best wishes!