First the sales reps lie through their teeth telling newbie TEFL teachers that only their TEFL certificate is accepted in China and that without it you will only get a kindergarten job. It is now 2018 and NEVER in the history of China TEFL was there a requirement for a TEFL certificate for foreign teachers! In reality, their certificate is recognized in only 10-12 African, East European, and Latin American countries since it is an online course.
Secondly if you go to duckduckgo.com and search TEFLonline or i-to-i with the key word of "scam" you will find three pages of complaints that do not show up on Google. Why? Because these two companies owned by the same guy in the U. K. buys thousands of dollars of Google AdWords and afvertisement which gets their propaganda and self-created reviews on page 1 and 2 of Google. When was the last time you searched 5-8 pages deep on anything?
Here is just A SAMPLE of what pops up on these scammers:
http://www.abroadreviews.com/warning-onlineteflcom-clever-scam
https://answers.yahoo.com/question/index?qid=*******0222AA7AW44
https://www.scam.com/showthread.php?*******-China-Scam-Alert!-Fake-TEFL-amp-TESOL-Certificate-Requirement-Fraud-Targets-ESL-Teachers-Teach-In-China-Jobs&highlight=OnlineTEFL
https://www.reddit.com/r/ChinaScamCentral/comments/6mb1ns/fraud_alert_onlineteflcom_and_itoi_are_the_very/
http://www.chinascambusters.com/
https://teflreview.wordpress.com/
You will find they are very notorious for they fake TEFL Teacher Internships abroad which are really regular jobs sold to their dumb customers at a 50% salary level for 3-6 months with an "internship" label. The employers are tickled pink with this deception and go along with it because they save 50% of salaries and do not have to pay for nor provide medical insurance or paid holiday nor overtime to "interns". All in all this U. K. group is a very devious bunch.