Car park fine

I left my car with blue disc indicating the time of arrival at a disc zone. The parking attendant issued me a ticket indicating that disc is not valid. I found the attendant at the end of the street and I questionned the reason for issuing me a ticket, the answer was I arrived later than the time indicated in the disc. She had a photograph of the disc along with car which shows the time of arrival on the disc was 30 minutes later than the time when the ticket was issued.
She knew she made a mistake and she said she will communicate this to the office to cancel the ticket.....
Now I have 5 days to pay the ticket fine, failing to pay within 5 days will increase the fine further. I tried calling the phone number of the office to know the status of this incident but the office is closed even today.

Should i pay the fine and reclaim it? or call the office again later this week.