need help with skript

[S1LENT_EG]

i cant get this skript to work the block wont replace anything i can do to fix it?

on break:
    if event-block is cobblestone:
        set {_cobble} to a random number between 1 and 5
        if {_cobble} = 1:
            set event-block to cobblestone
        if {_cobble} = 2:
            set event-block to iron ore
        if {_cobble} = 3:
            set event-block to coal ore
        if {_cobble} = 4:
            set event-block to diamond ore
        if {_cobble} = 5:
            set event-block to emerald ore

[belac136]

I'm not sure if this is the issue, but i think that your indentation is wrong, and you need a few elses. Don't take my word for it, because i have had the same problem and im new to skript, but i would do it like this:

on break:
    if event-block is cobblestone:
        set {_cobble} to a random number between 1 and 5

        if {_cobble} = 1:
            set event-block to cobblestone
        else if {_cobble} = 2:
            set event-block to iron ore
            else if {_cobble} = 3:
                set event-block to coal ore
                else if {_cobble} = 4:
                    set event-block to diamond ore
                    else if {_cobble} = 5:
                        set event-block to emerald ore