We do not insist that you purchase our services. We have published the books of many authors who have had their books edited before they approached us, and have helped many others design their own covers.
That said, we will not publish a book that is not properly edited or has a bad cover (usually clipart downloaded from a powerpoint presentation). If the author insists, we may simply print that book but we will not issue the book an ISBN. This is because we believe that the content within the book must be carefully and properly edited and presented.
If you approach us with a manuscript, we will explain to you why the book needs to be edited. Further, we will also explain our reasons to suggest either copy editing or substantive editing. We will also explain why the cover you have chosen for your book may not be the right one to go with, or why the illustration you have provided will need a little more work.