We have a retractable lead for Zoee and I stopped using it for about the same reason. I could not keep good control of her on walks. I find the regualr nylon lead works good. You might want to try a leather one, which may be stronger. Or maybe someone who uses halters find that works better. I've never used one, but want to try something like that with Zoee.
I'm glad they didn't hurt the kitty. Dogs will be dogs.