There are many ways to provide fake and unfair evidences for a signal provider. Also, none will trust a newbie who registered just a few hours ago, so you will need to use escrow services. However, after years of trading forex and crypto I don't trust the signal channels myself.
It is possible to fake evidences, but "unfair"? xD I provide anything that you would like (+ his free channel, which there you can check trading history by yourself).