How do I go about amending my return if I don’t have all the W2s on hand.

I filed my taxes and they said I was under a review. When my review was up they told me it was because I didn’t file all my W2s. Which I didn’t know I had more honestly. So he told me to go file them but I don’t have them I just looked on my transcript and see all of them I’m supposed to have. How do I go about doing it if I reached out to the company’s and they just keep saying they was mailed.