Character slot expansion

I just purchased a 13th character expansion slot and it’s not showing up. after just reading the forums it’s seems this is limited to 12. The shop item says up to 18.
If this is the case why was the purchase allowed to go through and how do I get the crystals refunded since did not receive/can use the item?

Character slots will expand in the future.

Hold ye horses

But are we sure the slot will be unlocked if If we have purchased the 13th slot? I am in the same situation and I am afraid that I spent 800 crystals for nothing.