How to attach Ring Battery Doorbell HD Video to Stucco Wall?

I bought a Ring Battery Doorbell HD video and had a handyman attach the plastic mounting plate to my stucco wall. No matter how I adjust it, tightening or loosening the mounting screws, it's slightly bent, deformed, and the doorbell won't click onto it securely. I found a "No Drill Mount for Battery Doorbells" on the Ring website which is supposedly compatible with my doorbell and would enable a no-drill mounting. I can't make heads or tails of the instructions, but I have a doorbell with original mounting plate, a secondary mounting plate that doesn't seem compatible, and no doorbell. Has anyone else encountered this dilemma?