Did you zero the front site post to that, or is that as low as it will go? My guess, if you zero'd to that position is that you did it incorrectly. Did you start with the base flush to the surrounding site base?
In the event that is as far down as it will go, then it needs to be sent back.
I would use a target designed to 50 yard zero'ing, so the grid is marked with 1/2 MOA grid, so your clicks will correspond, if that doesn't get you close, you are likely doing something wrong.

