My Five year old stuffed toilet paper down the toilet and blocked the toilet. How would you deal with him?

My, just turned five year old, was caught stuffing handfuls of toilet paper down the toilet at school which consequently blocked the toilet and required the services of a plumber. His Teacher spoke to me about it in front of him, he has been repremanded by her and by me, I have asked him to explain why he did it and taken away favourite toys. Where do I go from here? I am thinking of asking his Teacher to take him through to see the headteacher to explain himself, I think that may make him think. Am I being too harsh and how would you deal with it? Any advice greatly appreciated! xx