This is exactly it. I've also asked her straightforward questions like this many times, but she always says something similar to what you mention, or along the lines of "I want my content to be a surprise". This is of course complete bullshit, because an actual sex tape would sell much better than your average content, so it would make sense for her to highlight it as a USP. Basically, NOT saying something, is also saying something. In this case, that it is not a sex tape. If you were to get a clear answer, it's quite simple to get a refund, but this is something Mati also realizes, so she doesn't give clear answers.
As a side note, I don't even think Mati does the chatting on her OF. She is supposedly in France right now, but her activity is still in the middle of the night for the CET time zone. I suppose PPV's and mass messages could be scheduled, but it's not like your messages will be answered until morning time in the US.