How do I deal with a camping Hecarim?

Me: Caitlyn..

Caitlyn blows up Vayne on bot lane by abusing her aa range in early game to deny Vayne any farm whatsoever. Caitlyn does not however go too aggressive near enemy turret range because thats when junglers tend to gank. She gets in about two doubles in 5 minutes. So Vayne's Nidalee support finds Vayne hopeless and then decides to go AP mid. That's when hecarim comes out of no where and picks up a kill because the bastard is hella difficult to kite. K fine, I got ganked. Time for ward coverage and some passive aggressive farming while putting traps near the north brush. Hohoho Vayne is at 25% health then some pony comes in without any brush routes and its now a 3v2. So I e to safety, but the pony is too fast then i get feared then the jg kills me again. Then I guess we'd come ward the pony's jungle deeply and then take it from there. One at dragon, one at red. So then my security was regained. Placed more traps on gank routes. Blows up an amateur Vayne for awhile then gets ganked about two more times. Here comes late game and Hec is waay to tanky for me and my nexus exploded soon after. Where did I go wrong?

Build: Phantom Dancer, Bloodthirster, Botrk(for tanks), Brutalizer, Beserker