Stronghold – “The Barbarian Seven” [Campaign 6, Mission 3]

Good day! I need your help, comrades; I can't seem to complete this mission. I've tried various development strategies, but the result is always the same: game over. :( Here's the situation: no matter who I send – jaguars and saurians (centaurs) – they are immediately defeated. By the time I fight Kalindra, I have only one unit of each. The snowmen with their magic help somewhat, but they also don't last long against Kalindra. I've upgraded Reinforcement, Drain, and Cleave. There's no Restoration available in this save, but I've tried it, and the result is the same as described above. Also, I'm not connected to the internet. Unfortunately. :( Any ideas? I'm open to any suggestions, criticism, or questions. P.S.: I've been playing Heroes since 1999, and I've never encountered such a frustrating situation. I'm starting to get frustrated with my own helplessness. Or maybe it's time for me to retire? XD