No grievious two handed mace in shop

There is no two-handed mace available in season 14, the same as there isn't a Crossbow available in season 14 for Conquest points. It's actually very normal for there not to be every single weapon type available during each season. The same thing has happened in previous seasons but for other weapon types and in season 15, there may be two-handed maces available again.

If your preference is to use a mace as your weapon we can understand your frustration, especially if you happen to play a Dwarf, however if you plan on wielding a two-handed weapon this season then you'll need to decide between a sword and an axe.