article conflicts

I'm a freelance writer and I am in a situation in which I am not sure what to do. I'll keep it short. He paid $35 for me to rewrite all of the pages on his site. His instructions were
"Rewrite these pages"
"I need 100% unique content."
"The meaning has to be the same."

I just did a rewrite of everything, going off the topics. Turns out he wanted me to change "every 3rd word" so it passes copyscape. I didn't know that until after.

Anyway, he wants me to rewrite everything. I want him to be happy but he is asking me to redo 4 hours worth of work.

Not sure what the right thing to do here is. I could give him his money back but that negates the 4 hours of work I did for him. I could redo the articles but again, that is me basically giving up 4 hours of my time for nothing.

I feel like the fault was on his end due to unclear instructions and I should not have to sacrifice 4 hours of work because of that.

I am not sure what to do here.


ETA: I don't think he even checked all the articles (8) before he asked me to rewrite all of them.

For the sake of keeping the customer happy I would probably redo it. Changing every 3rd word is probably going to take less time than rewriting the whole thing. However, If you think that isn't fair since he didn't say that in the beginning then maybe ask him for an additional payment for the work already done.