Apparently many TEFL/TESOL providers lack actual accreditation. If you're in the search for a shiny new TEFL certificate then you might have come across the "We're accredited" slogan. The truth is that some of those who claim accreditation don't actually have it and for some it's a false accreditation. So they could claim it, but actually lack it. See this post.
In the case that they have it, it could be false. The accrediting body could be set up by the same company under a different guise. Or the TEFL company could have been scammed by an accrediting body. See this post.
Another catch many companies use is to host their course in some exotic location such as on the beach somewhere in Thailand. Who doesn't want to go to a place like that? Earning your TEFL will be like taking a vacation. Then there is the:
Yeah sure it's possible that you could make more money or get a better job, but it's certainly not guaranteed across the board.
ESLinsider now offers an online course where you can get TEFL certified online and by the way we don't boast any false TEFL accreditation.