Sorry to hear about the mishaps with the last guy!
If this particular project is just recreating the calculator page so it fits in with the Divi theme, i can do it very quickly for you - we can talk via phone as well if you like and if other edits need to be made across the website (seeing as you said the whole site itself was designed by the same person and had trouble understanding exactly what you wanted) I can do that for you as well if you'd like another project going forth. Outstanding bid is just for the single page.
You can check out my latest wordpress work with my client's site at: [login to view URL] and my professional record at [login to view URL]
Look forward to talking,
Frank