@YOSHIE have already given you the format of reporting a cheater or an alt account. But I would suggest you should venture your precious time into doing something very meaningful because finding accounts that have shared gas to each others isn't bad though but is very risky. However sending gas to another address doesn't fully shows that such person is a cheat or using alt, for such claims to be valid is when a user using same address or same telegram id and with same facebook profile in enrolling same campaign that could be automatically proven is true. Just @YOSHIE has already fetched out the two connected account

So be very mindful while sourcing out address that sent gas to each others.