Commuters living in Essex have been overcharged by up to £3 per journey for travelling into London.
C2c said customers using contactless to travel into the capital from outside the Oyster Zone had been overcharged since Sunday.
The company has apologised to affected customers and is working with Transport for London to resolve the problem.
In the meantime customers are urged to use paper or e-tickets instead of contactless payments.
C2c runs services from Essex in to Fenchurch Street or Liverpool Street.
C2c says in a statement on its website: “Due to an unforeseen technical issue, c2c is aware that customers using pay as you go with contactless ticketing for journeys between c2c stations outside the Oyster Zone (beyond Upminster and Grays) and Fenchurch Street or Liverpool Street from Sunday 8 June, are being overcharged by up to £3 per journey.
“This only applies to journeys that either started or ended at Fenchurch Street or Liverpool Street stations.
“C2c is working closely with Transport for London to resolve the issue and, in the meantime, customers are advised to purchase paper or e-tickets instead of using contactless (for journeys that start or end at Fenchurch Street or Liverpool Street stations) to ensure they are charged the correct fare.
“C2c would like to apologise to customers for any inconvenience this technical issue is causing. Customers are advised to keep a full record of all contactless journeys where they have been overcharged, and a further update, including details of how to claim a refund, will be shared as soon as possible.”
A TfL spokesperson said: “We are aware that, following a pre-planned update to the fares data within the contactless pay as you go system last weekend, some of the data provided by c2c was incorrect. As a result, customers travelling specifically to Fenchurch Street or Liverpool Street (National Rail) on c2c services from outside London may have been overcharged. All other contactless journeys are not affected by this issue.
“We apologise for this issue and are working closely with c2c to urgently correct the data, and are working to issue refunds as soon as possible to affected customers.”
