As has been stated in many threads (though it can still be difficult to find), here is a short list of best practices when searching for a reputable website in this industry:
-Read the webcopy. If the English they show their customers before they even order isn't good, it's a bad sign.
-Call the customer service numbers Thick Eastern European accent? Bad sign.
-Look at the site's claims There are no industry organizations that give awards to essay writing companies. The idea is laughable. Claims to have set the "industry standard" are suspect, and claims to have won industry awards are outright lies--there are none to win. The guaranteeing of grades is also a cause for suspicion; these essays are supposed to be used as models and are not to be turned in for a grade, and no one but the grader can guarantee a grade, anyway. If a site promises a certain grade, it probably means they have no real refund policy, so they can tell you whatever they want to get your money.
None of these signs necessarily mean that a site is a scam, but they are all warning signs. Essentially, then, you want a site with clean webcopy in grammatically correct English with standard word usage, a number that connects to someone who speaks decent English (answering machines are not necessarily bad signs--companies that don't employ dozens of people just to answer phones have more to pay their writers), and that doesn't make outrageous and impossible claims about its services