Solved Removing a variable of an item from the player's (error) inventory

[Pqngs]

I am trying to make a simple shop skript so when you buy an item it removes a specified price of coal (in this case) from your inventory.
But it doesn't work.

on inventory click:
    if name of event-inventory is "&8Are you sure?":
        if event-item is lime wool:
            close player's inventory
            cancel event
            remove {pickcost::*} coal from player's inventory # <- the problematic line
            add 1 to {pick::*}
            set {nextpick::*} to {pick::*}
            add 1 to {nextpick::*}
            play sound "entity.experience_orb.pickup" to player
            send "&aYou successfully upgraded your pickaxe to tier&2 %amount of {pick::*}%&7."

ERROR:
{pickcost::*} amount of coal can't be removed from an inventory because the former is neither an item type nor an inventory

NOTE: It worked when it was just a number of coal, not a variable of coal.

 

[Minecoll_YT]

Yes, because it's a list. How did you set the variable?

 

[Pqngs]

Oh no worries! I figured it out. Although i have another problem i'll be making another thread for it.