
No. If you're totally dissatisfied with the quality of the product, a credit is worthless for the same reason that you wouldn't want a "credit" for
another meal at a restaurant in compensation for a meal that you thought was disgusting. A credit from a writer or essay company is only worth something if you already know that you're usually happy with their work in the first place and that you'll be using them again. Once in a while, a project with flexible original specs about length ends up coming out to fewer pages than originally anticipated, quoted, and paid for, in which case I'll offer the client the choice between a future credit for the shortfall and a
pro-rata refund and they usually just take a credit, but it should always be the client's choice if the issue arises because of the writer. I just had one of those a few days ago: it was supposed to be 5 pages for 3 admissions essays that only came out to 4 pages because that was the most I could possibly get out of the info provided by the client without fluffing it up just to make the full word count. It was a new client and he chose the partial refund for the last page, possibly just to see whether I'd really issue it, which I did, immediately.
Conversely, if the client cancels for reasons totally unrelated to any fault of the writer (like dropping the course or something), then it's the writer's option to refund it or just offer a future credit, depending largely on whether the writer turned away other work in the meantime because of that project, or where the writer has already changed around other plans or inconvenienced himself to fit it in. If the writer has actually started
work on the project by the time it's cancelled (including "just" the research for it), then the writer's only obligation is to offer a future credit for however much of the time needed for the project hasn't already been spent on it by the writer. The general rule should be that the person whose "fault" the cancellation (or other problem)
isn't gets the choice between a credit and a refund.