You can return Fujifilm cartridges 

  • by mail (selected products only)
  • in person at one of their service centres (all toner products)
  • in person to your delivery driver when you buy directly from them
  • in person from the reseller where you bought it 

"Customers who have purchased new toner cartridges from our resellers, such as Challenger, may return the used toner cartridges to the respective resellers.”

Follow the instructions at their web pages linked below.