Mr Winspear said he was very disappointed, as he had planned to get the new iPhone model for his 19-year-old son, Andrew.
"If they had told me at the time I wouldn't have minded, it's just that they didn't tell me - if you're going in there to sign up on a new plan you're going to be OK, but if you're an existing customer you can't."
Vodafone had apologised to Mr Winspear and promised to notify him when the second shipment of iPhone 5S models were available for purchase with his voucher, but he said it was not good enough.
"I have been looking at 2degrees and Telecom but they will probably say you're going to have to pay breaking fees, but I don't think so - they are the ones who broke the contract first."
Vodafone said it was "putting things right" with Mr Winspear and apologised for not communicating the correct message. "We don't accept vouchers for the outright purchase of the new iPhones because of limited supply, and this should have been communicated to Nick when he re-signed - it wasn't and we apologise for this," a spokesman said.
"We are sorry for the inconvenience this has caused Nick, and for his disappointment. We handle customer concerns on a case-by-case basis and are putting things right with Nick."