Is your original headliner cloth or cardboard ? what year car did you install it in? By the sound of it they must have glued the foam back material to your existing cardboard. And know it falling down due to improper prep for installation or the wrong glue. I use the foam back on several Omni's and truck's also a 74 Dart. you must clean the surface with thinner thoroughly . And use the correct contact cement , Not trim adhesive, I would say to you if its a glue on, The installer should stand behind what the screwed up.
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