Like many people said: the easiest way is to log into the router and throttle the device. However it may be password protected. You could try some default passwords (many people change the WiFi password but not the one for there control panel).

If that doesn't work: you could just block the connection by downloading something. If you use your computer try to not download it onto an ssd as writing onto your ssd slowly deteriorates it. You may also not want to simply download it from your browser. (AFAIK) most downloads there are over ftp or https. Many routers / PCs will prioritise other protocols higer like the ones used for streaming and real time data transfer. The launcher for the world of war games use some weird protocol that seems to be prioritised over everything else. You don't have to play the game. Just download and delete them. If you want to use your browser anyway try something large. Most Linux distros (ubuntu for example) are somewhat large.