Using English - Copy Editing for persuasive writing

[ChineseHerbs]

How to edit ad copy and persuasive letters to make English correct and also feel good to read? This is my question because maybe some of you also are learning English and have this same problem.
English Editing websites help me because I am an ESL professional and I never know how good the quality because I must trust them to change content so it makes customers feel good and make an order. These websites are academic English and not sales. Right now I am writing articles for SEO and promotion, and I do forum marketing. Sometimes I do not need to edit, but sometimes I send all copy for editing and I am not satisfied.

[David Hunter]

The English editing sites you use, are they automatically correcting your copy, or is someone on the other end who is reading your copying and making edits to make sure it flows right??