I don’t think it will be a problem if you get the manuscript edited by an editing services company other than the partner company of the journal. Many journals have a partner editing company to help authors, but they are also fine with the author getting the manuscript edited from some other source. As long as the edit is done well, it does not matter where you get it edited from. There are quite a few reputable editing services company in the market: you can choose any one of them. In fact, Editage also has a language editing service.
Irrespective of which editing service you use, you should disclose that you have taken language editing assistance either in the diclosures or in the acknowledgments section. As per scholarly publishing best practices, any form of assistance with regard to writing, editing, or proofreading the manuscript should be disclosed.