The first thing, as indicated, is to show a copy of the course catalog to the registrar, and if necessary the dean of students. Ask for a refund, if in fact the catalog states what you have indicated and there was no announcement prior to starting the course or within the first two weeks of the course (usually the period during which one can withdraw with a full refund) that the instructor was not OSHA certificated and therefore you would not receive certification at the end of the course. If this fails, then an action in small claims court is your only alternative. It may also be a breach of the NJ Consumer Fraud Act.
I am curious if this was a public/private nonprofit college or if this offered by a vocational college? There have been news stories about many who hire people to secure students and offer student loans that are government guaranteed. This makes the schools less concerned with graduation, qualification, and more interested in payment from the loans.
If you think this is a good answer, please so indicate.
The foregoing is not intended to be legal advice upon which you may rely as I have not been retained for this purpose.