O'Brien got security footage from the reception desk showing the delivery driver putting the card to call in his mailbox without a parcel in his hand or knocking on the front door.
"We were quite frustrated with this, but I was shocked when after explaining the situation to their customer support we never received a single follow-up to our complaint."
He said the complaint was "totally ignored" after calling seven times between December 3-30, relaying the complaint each time.
He said the customer service representatives were apologetic and was advised someone would call him back. But nobody did.
"We persisted with calling them to see where the complaint was at, but despite endless promises of a fleet manager, team manager, or representative following up next week, next day, or even that afternoon, we never had any actual resolution," he said.
"Every time we'd call we've had to reiterate everything again," he said.
He said he was also hung up on twice during his attempts to discuss the complaint with NZ Post in December.
"To me it just seems kind of insane. A complaints system is not really rocket science. It shouldn't really be this.
"To me, it's no longer just an issue of a single driver. Or even a single employee.
"The monumental failure you have to have [with] a complaint with seven follow-ups just seems insane to me.
"There's a world where they get back to us and they say 'Look, we've had a chat with the driver, we'd discussed this as an issue. Thanks for raising this.'"
Speaking to the Herald on Thursday, he said he would've accepted a sincere apology from the company and reassurance that it wouldn't happen again if the company had responded initially.
That apology finally came on Friday morning, a NZ Post spokesperson confirmed.
"We wish to sincerely apologise to Austin for his less than ideal experience with us. Our executive team has reached out to Austin today to apologise for his experiences and to see what we can do to resolve this for him," the spokesperson said.
"We are also beginning an investigation internally to find out exactly what went wrong here. This is not the kind of service that we pride ourselves on and we are disappointed to have let our customer down in this instance.
"It appears that Austin has tried to contact us several times and unfortunately this has slipped through the cracks and we have not been as responsive to him as we should have been."
NZ Post said couriers should always attempt to deliver parcels as per instructions.
"In the event there is no one present to sign for the parcel at the time of delivery, we will leave a card to call. This is the process that our delivery team are expected to follow, and it is disappointing that this has not occurred in this instance."
