It's probably been my 4th attempt at beating Cerberus but he just kills me within the first 30 seconds of battle and its really really getting me frustrated

I can't use dispel because i dont have any and that 3-headed dog just keeps casting triple on itself and i can't do anything about it and soon enough he's already wiped me out. My question is how can i beat cerberus without using dispel or if that's not gonna be possible, where can i get myself some dispel spells?

is cerberus even worth getting in the first place? Do i really need it? If hes just gonna be of no use to me then im just gonna stuff the whole thing before i lose my sanity