What challenges do students face in online classes?

Are there specific challenges that international students face in weighing take my online class services. There can be language problems, cultural differences, and time zone complications to overcome. Has there been anyone who has overcome such hurdles. Are there services designed specifically for international students. How do you ensure clear communication and understanding? What about payment structures and exchange rates? How do you determine the legitimacy of a service in a foreign land. I would like to hear about international students who have utilized or thought about using these services.