Mr Wishnowski and his wife Maralaine Ferguson took over the business six years ago.
"We thought after the six-year term we would start thinking about transitioning to a new owner. Looking to sell it on, we had started doing a little research in that area before this happened. We don't have anything to sell anymore," Mr Wishnowski said.
Mr Wishnowski thought about moving the business and then selling but he could only sell the franchise in it's current location, he said.
It would have cost $130,000 to move.
He had not decided what they would do next, he said.
"At the moment we're concentrating on the work we had to do here, in winding up. The end of the month is quickly coming. I'm not thinking too much beyond that yet.
Mr Wishnowski said he felt for his customers.
"Old people still like to have a paper trail, 90 per cent of our customers today used cheques to renew their car registrations."
In a written statement NZ Post said given the proximity of alternative Kiwibank branches, Kiwibank banking and bill payment services would no longer be offered at the location.
"We'll be writing to regular Kiwibank customers to advise them of this change," said Robyn Dalzell, Head of Retail Operations at New Zealand Post.
"We'll also provide support to customers wanting to discuss using internet or telephone banking."
Kiwibank banking, as well as bill payment, postal and courier services, are still available at Bayfair Mall PostShop at 19 Girven Rd. These services were also available at the
Grey St, Cameron Rd, Cherrywood and Palm Beach PostShops.