I don't know anything about the company, but it really depends on what you mean by "didn't follow the requirements." If that means the specs you provided explicitly required a discussion of 3 sociological theorists and 2 pages per theorist (for example) and strict APA format and only academic journals published since 2005 as sources, but the paper you got was all only about 1 or 2 theorists in MLA and used old textbook sources, then your rewrite should be free to fix everything that obviously should have been done correctly as per your specs in the first place. You should also get at least an apology and maybe some money back if it caused you to miss a deadline.
But if you mean your subjective interpretation of the specs is different from the writer's and (especially) if you mean you actually turned in a paper that you thought was perfectly fine but about which your professor had some criticism, that's a very different situation. (I'm not commenting either way on how you should or shouldn't be using the product, but that kind of thing does happen sometimes, even with work provided by the best essay companies whose TOS prohibit customers from using the work that way. Some companies say they won't touch work that's already been submitted but in my experience, they may just have to say that publicly while quietly assigning the work back to the writer to fix it.)
In principle, writers are responsible to fix anything that's their mistake; but if you just have a different opinion about how the specs that are less mutually clear should have been followed or a different opinion (after the fact) about how you might have written the project that you paid someone else to write instead, and without explaining your preferred approach in advance, then the rewrite shouldn't be free but should be charged at a reasonable and fair rate because the writer didn't actually do anything wrong. Again, I don't know the company or what kinds of promises they make during that 7-day revision or amendment period. I have experienced both extremes (1. having to redo an entire project for free because I misunderstood the specs or used the wrong sources and 2. having clients come back to me a month or more later demanding more work to accommodate every comment from a professor who just gave the essay they submitted a B+ instead of an A). Mistakes can happen, especially to the most established writers who are busy night and day with overlapping deadlines for half a dozen customers. It's a lot of pressure and room for error, but in principle, writers should always fix their outright mistakes that could or should not have been done wrong in the first place for free and charge reasonably for other changes or edits afterwards that weren't mistakes. Sometimes, the customer is the one responsible for leaving out part of the specs, in which case, that's a paid rewrite because it isn't the writer's fault at all. Does that make sense to you?
Not sure how much detail you're willing to share, but to know what's appropriate or inappropriate, we'd need to see the original specs and at least the parts that you say are deficient.
