unfair chess. com things
or when someone does not understand the rule for en peasant, and accuse the other player who understand the rules as cheating..well, that is the rules and it is legal..
Chess.com is owned by a profit company, everything they do in that regards is technically fair - it's not fair for you but it is fair to them because that's the entire point of a profit company as they are going according to their own rules. If you play hide and seek with someone and they added some rules, that would be unfair but if they created hide and seek and you willing played it - then technically they did nothing unfair as the rules were existing before you played and it's according to their structure of the game. You could however always go to liches since it's owned by a non profit company.
The Abandoned issues can also be caused by either your connection or the server connection. I highly doubt they purposely added this bug so don't blame them for it. Every service will go through changes; they have to maintain the servers, they have to maintain the APIs, essentially every important component has to be maintained or changed at some point.
What especially is unfair? I want to help but I don't know exactly what you are referring to.