Technical issues makes more money

I booked a parcel (locker to locker this morning) I dropped the parcel of a little later. The Courier Guy phones me to inform me that the pin is incorrect. Double checked and it is correct. Now they say I have to rebook the parcel and pay for it again. There is no way! It is not my problem if they have technical problems. Seems to me this is a way to make more money.