Someone is trying to fraud me

I joined a sales call with a company over zoom and based on the information they provided me on the call I decided to invest $11,000. I then was told later that the deliverables they offered me which was the reason I signed up, was not actually available to me. Now I have requested access to the sales call and they have provided it to me via a google doc (the ignite call they gave me a zoom link). I know they have edited this call and removed the section where I was provided the information. I also know they can edit, trim and replace the original zoom recording, so I’m wondering how I actually gather the evidence that they have tampered with this and removed the relevant section. I was curious as the zoom call they did send me has the original time stamp on it. If they edit or trim a video, does it change the time stamp? Also I was not able to talk to a human from zoom support as I only have a free account. It said I could request the file meta data but still this is not fully proof and can be changed as well. I’m lost and I don’t know what to do here. I would truly appreciate any advice or support. Thank you