Before calling the maker screw the darn die down another quarter turn. Lube a case. Run it through again. See if you can push a bullet in with your finger pressure alone. If yes then call them.
If you call them. While you at the press on the phone with them. They will say screw the die down a quarter turn and try it. Repeat till three quarters of a turn. If the problem is then not solved they will mail you another sizing die.
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.