ORDER CANCELLED SAME DAY STILL NOT CANCELLED AFTER 9 DAYS!

I placed an order on 14th December 2017. Then cancelled the order on the same day as the item has the incorrect plug. I got confirmation email that the order has been cancelled, however, I am still being harassed with sms messages that the item is being delivered, is being delivered, cannot be delivered etc. All I need is for the order to be cancelled and my money refunded. Each time I email, another reference number is generated, another operator tells me "apologies for the inconvenience...." The delivery date has now been moved again to tomorrow. How do I make this go away? Order number ********** 7