E-topbiz.com - PTC Script Bugs

I order the Hits 4 Cash 1 script from E-topbiz.com on Aug. 28, 2007.

I sent the owner a e-mail the same day telling him that his script has a big security bug allowing people clicking on other user's links and also some other bugs such as it's not possible to enable a link using the admin control panel or change the message that user sees when he logins.

The big problem is that everyone, without even been a member, can click on many users links and charge the advertisers and me lots of money. For example:

[url]
[url]
[url]

The owner of the script said in other websites that if there is any bug they will fix it or refund. I got only 2 reply from the owner sending me the license code (but I had already report him the bug, asking him a refund) and another one asking me "why someone wants to click other peoples links?". From his reply I understand that he doesn't care to fix it.

So what would you do in my position? I want to avoid a chargeback but I can't communicate with him.