I felt that way, too, first time, and at the time I had my first two Dots (gen1) One was really hard to push in, another less so. So, I realized these little plugs are very tight. So I pushed into the less-tight one first and after a good solid push with male jack I heard and felt it snap in. So, I worked on the other one and got it in, too. I also pulled them out right away and they were less tight to plug in again.
Anyway, I felt it was Amazon's problem if I broke them, but all it turned out to be was tight little buggers; the jack must be flush with the Dot's plug for all three connections to work.I also got some gen2 Dots and same story. The Dot plugs are made with good hard spring steel!