If you didn't write the dissertation, it's not yours to submit. It's one thing to write it, and have it edited by someone else (to clean up spelling mistakes, grammatical errors, etc); it's completely different to "surf" a site for a pre-written dissertation, or to even tell someone else your ideas and let them do the writing. That's VERY unethical, and unacceptable, in my eyes and the eyes of many teachers/professors.
Tutoring is not the same thing. When someone tutors you, they are basically teaching you one-on-one. They are coaxing you to find the correct answers; they are breaking down the questions/problems until you understand them, and then walking you through until you find the answer yourself. A tutor doesn't write a paper for you, they answer your questions about writing the paper. (Ghost writers write papers for you, and when it comes to dissertations, it's unethical to use a ghost writer.)
I've not viewed the site you mentioned, but I'm curious why you felt the need to link to it more than once. I would hope my own children would not use a "service" for their dissertations, except maybe an editing service.