I find many expect these to convert it back to a proper Word document. Time after time the failure is a simple one. The lines are not in their own paragraphs and other failures.
My suggestion is to NEVER PAY for this unless the demo was acceptable.
Also be sure to ASK THE AUTHOR of the document for the source and be sure you have rights to the document. In today's world I find many make grand assumptions that we have a right to copyrighted material.
Recently I found this PDF to Word Converter. Sounds holding many functions that online software does not have.How about it?