I have noticed, that when I clic on search ads, my ip blocks the landing page of the ad. I have two questions:
1. Does that clic cost to the advertiser?
2. Is there any feature that can help me as an advertiser to avoid that?
So many website are blocked by some ISP/Country/Area. If may be that your system/browser/some software setting blocking that page.
If your IP is blocking that landing pages or anyone system that blocking the landing page. Its will be counted as clicked and billed as click.
But, so many time if google system detects that it system fault, then they don't count it click and in that case advertiser don't need to pay and those click automatically excluded.
As an advertiser, you can enable tracking and also can check your website/server access log to see about those issue.
Hope it help.