I got a speeding ticket but I think the camera got it wrong

You can request a review of an infringement notice from the issuing authority, and you should do so before the fine becomes due, providing evidence such as photographs of the number plate, receipts or location data showing you were elsewhere. If the review is refused, you can ask for a court hearing, in which the prosecution must prove the offence and you can present your evidence. Under the Land Transport Act 1998 demerit points accumulate, and reaching 100 points within two years leads to a three month licence suspension, so it is worth defending errors. If you are the registered owner but were not the driver, you may need to nominate the actual driver. Check the notice for the deadlines, as missing them can cost you your review rights.