The main thing here is that the inspector needs to clearly document the violation! If the road markings aren't visible in the photos from the report or are barely visible, that's already grounds for contesting it. Try to get a copy of the report with all the photographic materials - they should be attached to it. Compare them with your own photos taken the same day from the same spot and at a similar distance.
Also, keep in mind that if the markings are worn down to the point where they're not visually readable, then technically they're no longer valid markings under traffic regulations. Without visible markings, it's hard to prove a violation - the inspector can't fine you for breaking something you can't see. Take several photos from different angles and with different lighting - this will support your argument in court or when filing a complaint with the traffic police.
Just remember that if it's a former paid parking area, questions might come up: why aren't the markings being refreshed, who's responsible for that. Sometimes this works in your favor, sometimes it requires additional evidence. Either way, it's worth contesting - the key thing is to gather everything carefully and don't delay filing your complaint!