So, I sold my 20" iMac on Trademe for $550 because my partner and I needed money for a bunch of things, including vet bills for a malnourished stray cat that we found living under our house. The computer was perfectly functional as far as we could see.

The buyer came over on Friday afternoon and had a play with the computer before agreeing that it was in good condition, handing over cash and taking it home.

That night she sent through an email saying that she had started to notice faint lines running down one side of the screen. She asked whether we knew anything about this and suggested that we come to view it.

We stated that we had never seen problems with the screen, and reminded her that she had viewed the item before taking it home, acknowledging that there were no visible issues at the time. We asked her whether she might have knocked it during transportation, gave her the number of a good repair place.

She then replied saying that (1) she believed the lines were indicative of a longstanding issue and therefore our responsibility, (2) that she was not willing to have it looked at by a professional, (3) that they could not have possibly been caused by bumps during transportation, (4) that the lines were barely noticable but that she was a digital artist and therefore needed the screen to be in perfect condition, (5) that they simply had not been noticable at the time of viewing due to "dark desktop wallpaper" (it was a photo of bright green leaves), and (6) that she wanted a refund.

I replied stating that (1) she had inspected and approved the item at he time of the sale and therefore issues that arose after the purchase seemed unlikely to be my responsibility, (2) that the majority of the money had been spent at the vet, and therefore I was unable to provide a refund unless legally obligated to do so and I am a student and will have great difficulty saving up enough money to pay her back.

She has not replied to this email as of yet, however I wanted to check with knowledgable people as to what I am legally responsible for. Am I obligated to provide her with a refund? It seems unfair that an issue that arose post-purchase would be the seller's responsibility, as the buyer is likely to have caused this problem herself.

Any thoughts would be appreciated :-)