Why will anyone promote first of all if he has fixed matches? To get attention of the all the people and then finally the players will be questioned? Hence all the matches that you see here and there available publicly that is claiming to be fix matches are only scams. They just send you some fake screenshots to make you believe that yes they have won many times. Now a days it’s hard to get fix matches.
I believe that even with all the necessary evidence, there will be people who will bet and trust this, as it is a relatively easy profit and depending on the approach and what they say, it will be more convincing.