Unfortunately that is true.
That is very hard to say and quite random. If you are in a similar timezone as us, it can often be within minutes, but if you are not, if we are busy witih life or other things, or if the issue requires some research or discussion with othres it may be hours or even days sometimesā¦ 
That said in those cases I strongly recommend doing what @Strawberrycake said. If the opponent is clearly trying to cheat, just call a mod, wait a minute or two and if noone comes soon just leave the game. Yeah you might lose on time, which we will only annull (meaning you wonāt get points for victory), but I find it better than wasting time on someone like that. Usually their rank is inflated anyway because of the undeserved wins before somebody reportsā¦