Just found this on the club website
"Update: 4:50pm (18/07/19)

There was a small discrepancy with Adult tickets for the trip to the DW Stadium. Initially we were told Adult tickets were to be charged at £28.00 per person – however after further consultation with the hosting club, it came to light that this should’ve been £25.00.

To avoid any further inconvenience to those who have already bought – £3.00 will be refunded back onto the card used to purchase. Please note, this can take 3-5 working days to appear on your bank statement.

If you didn't use card to purchase or have any further enquiries – please contact the Cardiff City FC Ticket Office on tickets@cardiffcityfc.co.uk"