Late delivery

I placed an online order, click and collect on the 13th December and it was suppose to be delivered on the 24th. I haven't received my order and when I try to get feedback regarding when I will get my order the customer service agent said once the courier company has the order Mr Price can no longer track it and they can't ask the courier on my behalf. I tried explaining that I will no longer be at home from the 2 Jan, and asked if I can get the items shipped to another store and she said that my only option is to cancel the order once it's ready to be collected. I really want those items and they are out of stock so I can not order them again. @mrprice isn't there an alternative solution. And why can't I cancel the order before it has been delivered to the stored? My biggest issue is I am waiting for the delivery to arrive on an unknown date and if I choose to cancel the order once the items have been delivered I will still have to wait for the refund to be processed.