Giant Don's Flooring America

I got the job done in October , but it's still not good. The floor keeps falling apart, and they tried to fix it two or three times. The latest attempt was in April when they came to fix the stairs. However, the adhesive started coming off, and now more than two stairs are detached, and two others are loose. I contacted the manager at Don's Flooring to fix this, but he didn't follow through. When I talked to him on the phone, he didn't seem sorry, more like I was bothering him. The manager tried to backtrack on his previous statements and mentioned using a new glue to fix the flooring. I've dealt with the owner, the manager, and multiple installers, but they just can't do it right.