about academic proof-reading, what to do in this situation?
I don't have any advice about who to use, but I do suggest that you look to the long term. Try to find a person or a service that you will be able to work with on future papers, not just the current one. The person will get used to you and how you write and so the task will go quicker and maybe cheaper in the future. 

Don't look for the cheapest service, I think. Your English skills will improve over time, but you will probably have a better experience if you can establish a relationship. You might even get writing tips from such an editor if you ask, after the person gets some familiarity with how you naturally write.