They should have geotargeted and not used Adsense... mistake only a novice would make. They should read at least a Dummies book on AdWords or just outsource a campaign to someone competent.
When you know what you're doing, AdWords DOES work.
The issue is the spankin'-new PPA program. First worlders could engage in lead-fraud, too, so geotargetting isn't a sure fix.
You can tighten a PPA program so it only pays for paid signups, not leads/trials -- but then the fraudsters can dispute the credit charges. I don't think you can reverse the PPA commission to Google when, 60 days later, the signup money isn't there.
When you know what you're doing, AdWords DOES work.