I'm not 100% I can help you out, but I'm willing to try. Without the actual file, I can not guarantee anything.
If you contact me through chat with a download link to your video, I can try to repair it. Can give you an answer within 15-30m from the moment I have the video file available to me to inspect it.
If I manage to do it, then you can accept my proposal and I'll send the repaired video to you.