Sara,
I have only heard of a few instances where someone was turned down for a job because of the wrong alphabet soup on their certificate.

Example: Madam Wongs House of Whoopee and English Language Academy runs a TEFL program for soon-to-be teachers, as well as a school to teach English to the natives. They will only hire their own TEFL certified teachers. The academy will blab about how TEFL is the superior certificate, but in truth they will not even take TEFL certificates from other schools. They need the teacher openings at their academy for their own newly trained teachers. Do you see the circle here?

Overall, I dont think anyone cares what acronym is on your certificate. What is your background? Do you have experience teaching? Whats your education? These certificates are not even needed in many jobs, contrary to what the teacher training programs will tell you. Dont get me wrong these certificates will only help you, if for no other reason than to look good on a resume/CV. But they are not always a requirement. You have nothing to lose in trying to find a job without a certificate. All they can say is no. If they do then you take a certificate course. Hope this helps.