The thing is, proof of transaction isn't enough to say they're alts, they can make an excuses if those accounts is his friend or made a deal of buy a digital goods etc. Moreover the @OP made this report without a proof of they're cheating in the same campaign. He's just think if there's any connection whether it's a transaction or somewhat are considered a worthy negative tag, but the truth is anyone can have multiple accounts as long as they're not doing a bad thing.