Buyer is pressuring me to work more after delivery his website

[ahosania]

I have delivered a fully designed website. He also gave me a five-star review with good comments. After about more than 20 days, he is telling me that his website not so good and telling me to design again. When I have logged into his website, I have seen all themes and plugins are changed.

Now, he pressures me to design again. Please help me with what can I do now. He is telling me, If I do not do this he will submit a report against me.