Tier 1 Tech Nation Endorsement Refused

Hello,
I just got my Tech Nation endorsement refused saying that I have provided evidences from one employer only (which is not true). Can you please suggest, is it worth putting it for a review and are there any suggestions on how to fill the form? My form reached Tech Nation on 8th December and they took decision on 12th December - which looks a bit haste to me.
A fresh application later will not be possible, as I had collected lots of letters from CTO and Director levels, which will be extremely difficult to get again.

If you are confident that you have provided 2 letters on letterheads from 2 different employers under in-job category, then please go with review. I hope you have worked with both those people in the past for sufficient duration as letter should contain details about their experience in working with you.