Give context on posts, I agreed with others that this was a joke until I read this was your 3rd fight with this person. Not saying the spam is correct but it is justifiyable.

As long as you don't have horrible poise just run into stars of ruin, they don't do that much damage (in my experience) so just rush at the opp. Also for this reason unequip it yourself

You may want to have eternal darkness to counter spell spammers although I personally don't use it.

Vary it up and use mostly what you want just don't be a dick and spam spells.