An Auckland small business owner estimates Vodafone's move to ditch its email service will cost him about $20,000.
The telecommunications company is closing down its email services from November, affecting addresses including paradise.net, clear.net and vodafone.net.
The company said this week it hadn't kept pace with changes in email technology and its own customers had complained the platforms weren't delivering the sort of service they wanted.
Clients who needed help setting up a new account would be steered to what it called the email experts, Google Gmail and Microsoft Outlook, and anyone still wanting to receive emails to their old account would get a free automatic-forwarding service.
But Auckland consultant engineer Gilles Altner told Nine to Noon he'd found in the past that changing to a different supplier was not easy.
It was possible to do so with his own computers but there had been problems in the past with the computers of his clients, which meant he sometimes did not get emails that he was expecting from them.
The email service would look for his existing paradise.net account and not find it, because the domain name was linked to a different account, he said.
"When I tried to [switch] last time, when I wanted to change to Spark, I had to go up to the third level of technical adviser to try to resolve [the technical problems]. In the end I knew as much as they did about the technology."
The problem that developed was serious, he said.
"I did not get emails any more, it was as simple as that.
"I had to backpedal, I had to go back to my original supplier, I was on the phone for hours.
"I am calculating about $20,000 in lost income and costs if I have to go through this again."
Mr Altner said he planned to complain to the Telecommunications Disputes Resolution Service.
A similar issue arose when Spark moved customers to the Auckland cloud company SMX earlier this year.
SMX chief executive Ian McDonald said there would always be costs involved in switching to new suppliers, and while they could be quite low for most people, they would be higher for businesses.
Emails could get lost during a transition but this problem was resolvable, he said.
Mr McDonald said it took about nine months to complete the process of taking on Spark customers.
Vodafone has been approached for comment.