customer emails 39 times in 3 day

[flamingcolors]

I had a customer that had a problem with a product    

I said I would replace the defective part 

at this point with in 3 days he has emailed over 39 times about the same thing

So I refunded his money   now he's emails about the same part

he stills thinks he is entitled to it after the price of it has been refunded to him and he stills holds the product

 39 emails in 3 days this person has issues  how do I block his emails I have already blocked him from buying