Thanks for reaching out and we're sorry to hear about your cot! Unfortunately, we do not carry replacement parts for the REI Co-op Kingdom cot, which doesn't leave many options to repair yours. While it is a long shot, you may want to keep your eye out at your local REI store garage sale. You may come across a Kingdom cot there that has the pieces you need that are in good enough shape to salvage your frame into a functional cot again.
We're sorry we don't have any better options for you, good luck!