''Hi Amsi,''
[https://www.youtube.com/watch?v=XbSum8DaJGo|Firstly don’t take out the cartridge or try to], this could expose the film, which isn’t what you want to do, otherwise it will kinda like activate the film. But that might be the only way out, and you most likely have tried to do that.
The Film roller may have malfunctioned, there is a mechanical roller in the camera which is used to eject film from the camera. You could always try to slowly pull the black film cover from the slot. I am not entirely sure on how to help you, but if it is new, then get a refund. I’m am not sure what condition your camera is in (battery wise) but you may need a new battery?
[[Fujifilm Instax Mini Eight Troubleshooting#Section__Film_not_developing_ejecting_out_of_the_camera]]
If you do want to just open the camera and pull the cartridge out, do it in a [https://www.youtube.com/watch?v=NcqHb21TXxk|very dark place] so that the film won’t get exposure and so that it can be usable.
''Hope this was use-full, and I wish you luck!!''