We can't remove an advertiser based on an e-mail without concrete proof. We understand that this may feel unfair and sometimes we would see it differently ourselves, but otherwise everyone could just make false reports about one another and competitors can easily e-mail each other off the website.
This however doesn't mean that reporting an unpleasant experience to us is useless - all reports we receive are being registered and as soon as we see reason, we will act. We never make further statements about this, but it goes without saying that we also benefit from reliable advertisers. It won't help to report an advertiser more than once.