A job for profesionals only.
Have talks to a online film processing site or local store who transfers from video to cd/dvd with modern advancements in technology they may be able to ‘iron’ out the crinkled section during transfer to cd/dvd.
An alternative would be to contact the makers of the cassette as they make them they would have the knowledge if it can be done or not.
Explain why you want to try and save the film.
Good luck hope you have success.