lots of fake signups

dear Admin
please you have to do something for scammers on this site. i have denied almost 15 fake signups in last week or so and haven't got a single real and valid signup.
you know it that advertisers are as important for PTC sites as their users so if you don't do something about these cheaters soon then it will drive many advertisers away.
i am a small time user so i may not affect your business but if this happens a lot then it will be a huge problem for all of us.
please sir make a rule that if you are denied like 10-12 times , users earnings will be forfeited, account deleted and IP will be blocked