''Within half an hour, I had a call back. I said, 'Are you from Spark?' ''And he replied 'Yes'.''
The man, who spoke with a foreign accent, told her he was ''checking this, that and the next thing and that I had so many errors on my computer''.
''I was questioning him all the time, asking if he was Spark ... and I would say 'I'm not sure about this'.''
He told her to turn off any mobile phones or tablets, and later got her to open a bank account with BNZ.
The scammer told her to ring BNZ and change a password following an error when using internet banking.
The woman rang BNZ on another phone.
The money had been transferred from the woman's Westpac account to BNZ, which had placed a hold on it.
After hearing her story and seeing $16,000 was about to head offshore, a BNZ customer service representative told her to end the call with the scammer and turn off her computers.
When she told the scammer she had to go, he became angry and shouted at her.
He told her the money had to go to Dubai, but ''I told him that money is not going to Dubai. It is going to my bank account and nowhere else''.
That call ended at 2.30pm, almost six hours after she was rung by the man.
Westpac told her the $16,000 the man tried to send overseas via the BNZ account included $14,000 from her credit card, ''which made me feel sick''.
''I just feel so stupid I allowed this to happen, but I genuinely thought I was talking to Spark.''
Sergeant Kevin Davidson said another Mosgiel women laid a similar complaint with police this week.
That woman gave control of her computer to the scammer, who withdrew $3000 from her bank account.
''We're just asking people to be vigilant about the information they give out over the phone regarding their computer details,'' he said.
This month, Spark issued a warning about fraudsters reportedly telling customers their services would be cut unless they changed their settings or cleaned up their computers.
Spark acting head of customer services Bridgette Dalzell said in a statement: ''The most important thing to remember is that we will never ring customers out of the blue and ask them to view their computer remotely, to provide banking or credit card details, or to log on to their online banking''.