Players not getting refunded

I have at the no Remove - Normal - Refund this:
"Work Bench Level 3": {
"workbench3": 1
}

But when players remove they don't receive the workbench I an error shows up at the console saying that the player couldn't get refunded because the item does not exist?? I also tried with " workbench 3" but had the same result...

Image: http://prntscr.com/lv193g

hello, try this
    "Work Bench Level 3": {
      "work bench level 3": 1
    },​