To be honest the "guarantees" should have been the warning sign, as usual completely unrealistic.
"You can order a First class paper from us and be 100% confident in your grade. We also write papers for 2:1 and 2:2 Standards. Whatever you request, you are guaranteed to get it." - Cock and bull only the marker can ever guarantee the grade of a paper.
"If it happens that our writing or editing service doesn't meet all your initial expectations, we will revise your paper for free as many times as necessary to finally satisfy you." Either a writer answers the original question or they don't, no one makes endless revisions for free if they have met the original spec.
There aren't usually any "hidden clauses" the terms and conditions which most customers evidently never bother to read usually completely discredit the guff "guarantees" made anywhere else on the page. Evidently the case on this site.
When it comes to guarantees less is sometimes more...