recommended and reliable proofreading services
Have you tried getting the proofreading done within your own university?  This is not made explicit in your question, but my guess is that you are not a native speaker of English and you are writing in English.  If you are attending an anglophone university there will probably be places where you can just show up and get help on proofreading your paper (the humanities version of drop-in tutoring).  So I'm assuming that you are not attending an anglophone university.  But at (almost?) any university there should be faculty and students who are working on English writing specifically. Can you find a student who is willing to help you?  Perhaps you may even be able to offer some other academic service to the student in exchange.