Because SR Support investigates these things when they are able to, and yours was an easy case. As inigo already stated, they are doing the best they can to weed out the scammers. Some cases are more obvious than others. Some cases are easier to solve than others. Some cases are more complex and take longer to come to a decision about. Anyway, I'm done wasting my time trying to explain SR to you here when all you want to do is bitch about how you think it was unfair that they banned your vendor account for feedback manipulation. Done here.