Poor Customer Service

My daughter bought a parcel on the local online store and the delivery has been outstanding for a week even through she has been advised that the parcel is on the way. The Amazon agent Graham (assuming that its not an AI bot) I dealt with was unhelpful as his answer was that I should follow up with the Courier Guy. Courier Guy for days have been advising that the parcel is due for delivery but never deliver. The question to Amazon is where does their responsibility for fulfilling the sale end? When they hand the parcel to a courier who may or may not deliver on their behalf. And if I wanted to cancel the order, again I was referred to deal with the Courier and refuse the order. I didn't not buy anything from Courier Guy! Shocking customer service