Xd there is no way he coulda beaten just the longbows + falcs, forget the muskets. Were they by any chance imperial units? otherwise it is impossible without trying to get your units killed. longbows with basic micro can beat even vet sepoy. So the only possiblities are
1. He hacked/deckhacked. getting some early upgrade cards can reck havoc on your units.
2. Your an idiot, although i don't think this is the case
3. You reacted late, and he killed your falcs before you got to his fort, and fort protection+ sepoys killed the rest.
DISTISOP
ESO: Blitzkrieg_Mario
Prefered civs: Hell, I like them all.
Rank: TWC PR 18 (master sergeant) TAD PR 17, Vanilla PR 12
Clan: Triple Entente
Favorite games: Dofus, AoE 3, Tremulous, CoD 4, SSBB, Urban Terror