How to counter heavy cav archers?

I was playing a 2v2 BF game that we did eventually end up winning, but what happened was we basically wiped both their bases after literally like an hour and a half of pushing.. the problem was by this time one of them had a huge eco banked up and so although his eco was dead, he managed to somehow create literally (I checked in achievements) 196 Heavy Cab Archers + 4 trebs and it was nearly impossible to kill.. I figured since we had destroyed all his houses once we killed the heavy cav archers then it would be over, but it was just so hard to defeat because I could only send maybe 100 max troops at him because of pop space. Also I honestly just don't know what to send vs 196 Heavy Cab Archers. I tried skirms, melted. Halbs + skirms? melted. Halbs skirms and paladins? Didn't even get close. Eventually my teammate who had been cleaning up the last of their eco cornered him with me and he died, but I don't even remember what exactly it was we used to kill them.

So yeah basically what I'm asking is what's the counter to cav archers?