Phone bought of Ebay breaks after warranty

[senelzdek]

I bought a HTC Sensation XE off Ebay from cellphoneforever. The seller has a rather high feedback score so I deemed it to be safe. The warranty (specified by the seller) was 90 days. I bought the phone 5 months ago but when I recieved it i did have suspisions as it was a bit laggier than other, identical phones. Now the phone has completely stopped working and 'bricked.' I contacted the seller and they said they could not do anything because the warranty period was over. They told me to repair it myself. I contacted HTC seeing they have a 1 year warranty and they asked me the IMEI number and they said it did not appear on their records. This only further raised my suspisions. It is much too late to open a Paypal case and the phone was bought from Hong Kong, whereas I am in Australia. What shall I do now? The phone was not rooted now was any damage inflicted by myself.