If we add logic to this problem we will come up three possible scenarios:
1) Google has a problem on their side and is showing your ad to non-US searchers.
2) You did not set the geotargeting right (re-check).
3) Their is a problem on Hydra's side.
After we take a look at these logical constraints we ask ourselves, how can we fix this situation per the variables listed?
We shall take it step by step.
1) and 2) can be tackled easily. Check out the referring logs and see if it came through country specific Google domains (google.co.uk google.cn etc). If it did then either 1) or 2) or both are true. You can fix this by e-mailing Google your logs and update them on the situation (but be forewarned you're account is probably going to get banned.) To further your case, take the list of 100 clicks and extrapolate time and IP to each case. By doing that you can show that the last 100 clicks to your site were from X ip in X country (not the US) during the times your campaign was active, and so you were being charged for non-US clicks, when you specifically stated you only wanted US clicks. Now, if you fucked up on your side and left the geotargeting on then Google will not help you, just cut your loss and redo it right. What was I going to say. Oh yeah, 1) and 2) are tackled.
3) Talk to your network and tell them if they are geotargeting right.
All in all I've never had this problem either. Most likely you fucked the tracking (for example, Afghanistan is NOT apart of the US).
/sohigh/:rasta::rasta::rasta: