I can't use a shim, the fit is too tight. I can't increase torque or I will bend the seatpost.

Now what do I do? Should I send it back and have SOMA cut off the eyelets, file the area down so it is smooth, and repaint the area? That way I can use a seatpost clamp?

I spent a lot of money on this build, a slipping seatpost is absolutely unacceptable, it renders the bike unrideable.