I'm sorry to learn of your difficulties OP - that's what makes me so disgusted with these morally-bankrupt paper-mill services. They exploit the situations of students who are already vulnerable.
But I warn you here and now, if you try this approach you'll likely be caught. Plagiarism detection software is unlikely to flag up a 'paper-milled' essay, and a good many providers of this morally-dubious service will reassure you that the essay is a one-off and written for you only. BUT ...
Don't be lulled into a false sense of security by this. A dissertation supervisor will pick up the fact that it's not your work easily, and instantly. After three years on a course they know you, they know your work, and they've seen how the work has progressed during supervision meetings, if you've been attending. And they can easily compare your previous work to see if its compatible with your own grade profile and style of expression. Lecturers are practised at this.
The question, of course, is whether the university can prove it. But I once detected a paper-milled essay and before progressing to an Unfair Means panel, the student was called in for a viva. By the second question it was so obvious it wasn't the student's work that the situation was painfully embarrassing. The dissertation was failed, and because it was worth 60 credits of the final-year total, it dragged the overall degree result down to a Class 3.
There is always a better solution than cheating, OP.