Shijiazhuang Yitong Buick 3m film is true?

The 3m film I bought from the car cracked in less than a year. It is located in the glass film of the co-pilot. The co-pilot hardly sat there. When I went to Yitong Buick, I said it was artificial and irresponsible. Obviously, the film cracked by itself. He also said that if you want to change it, you have to go to a professional institution for appraisal. This shop is dark. Don't buy a car here.