Is it against the terms of service

They cannot nor will not do anything about this. Your only solution is too keep fighting your way through and show them you mean business. Yes its a bummer that even bullies on a mobile game exist (i have some in my shard too that hate giving up top 10 spots) but all you can do is not give into them and hope they stop and see that people dont fall for their bullying. Thats what I do and sometimes I will waste 150 crystals just to show then Im here and here to stay. Im sure it annoys them but thats their problem. And no i dont climb all day long just in my hour or hour and a half depending on my spot and who I need to go through and have a pretty good idea whos climbing before me. Hope this encourages you some what. It stinks but its life.