How do Slavs best byz? (Noob question)

I know that, theoretically, Slavs should be much better than Byz and overpower them. However, last time I had this matchup I was anihilated by a big ball of heavy camels+arbalest.

Game was rather even up to castle age (my scouts did some damage, but he towered my only wood causing severe damage). Then in castle I went for mass knights while he starting adding camels. That made riding with knights not possible, because camels can chase them (unlike pikes). I kept massing knights and hoped to overpower the Byz camels in imp where they miss some upgrades. Byz was faster to imp than me and had time to prepare some upgrades. Finally he did a push of siege ram + heavy camel backed up by a big ball of arbalest, which I lost against (even with a lot of fully upgraded cavaliers)

First mistake I realized is that arbalest were shooting from a hill during the decisive battle. That was bad. But even if I had avoided that, how do I beat them? I should not give them time to get to that composition, agreed, but how do I put on pressure if he is chasing me away with camels all the time? Pikes+siege push?

Context: 1850 HD (noob with build order knowledge, e.g. 21 pop scouts and such are common things to see)