As JB points out you may well have been speaking to an HR person who has no flying qualifications and no knowledge of what a JOC or a type rating are. If they have a list of requirements that state you need a JOC then that’s it in their eyes, if you don’t have a JOC you don’t meet the requirements.
If you don’t get anywhere with speaking to a pilot, try approaching the TRTO where you did your rating, if they run JOCs as well as ratings they might be willing to issue you with a JOC certificate based on your performance during the rating. If not they might be willing to issue you some sort of formal letter or notification that the standard required to pass their rating far exceeds the syllabus of any JOC.
If that doesn’t work you may have to bite the bullet and sign up for a JOC, or of course you forget that employer and continue searching elsewhere.