How to Deal With Serial Refunders?

Odds are that we have all experienced the serial refunder in our time in this business. It seems to be the worst with digital products such as clickbank items. The customer makes their purchase, receives their product and instantly files a paypal claim or a credit card chargeback in an effort to obtain a product or service without paying for it.

I can accept that there will always be these types of people pulling this scheme, but I am dealing with someone who is taking this to a new level. The customer purchased a product and received the digital item from me instantly. They then proceeded to file a chargeback with their creditcard and of course they will win 99% of the time. But one month later they filed a charge back again for the same original purchase. They only made one purchase from me but attempted to get their money back again after already getting it back a month prior. Then 2 months after the purchase they filed the chargeback again. Attempting once again to get more money from the original transaction in which they had already been reimbursed, not to mention got the digital product. I assume this will go on until they get tired of it, but most likely they are doing this to multiple people and preying on internet marketers.

How would you handle this situation if you were in my shoes or if you are going through the same thing yourself in the past or currently?