Letters have been sent to South Staffs Water customers affected by the data breach

Customers of South Staffs Water have said a cyber attack has left them feeling "vulnerable" and "worried".

The water company announced last week bank details from its database could have been accessed and potentially leaked on the dark web during a hack in August.

Letters have been sent to those affected and a third-party company has been appointed to help protect against fraud.

However, one customer says he can now no longer access his money.

Graham from Pelsall told BBC WM his debit card was cancelled after he informed his bank about the incident.

"I can't get any money out because I've got no bank card," he said.

The concerned South Staffs Water customer added: "I've had to change my email address, username, password and memorable information to log into the bank.

"It makes you feel a bit vulnerable."

South Staffordshire PLC, the parent company of South Staffs Water and Cambridge Water, said it was liaising with the National Crime Agency following the incident on 16 August.

Names and addresses of account holders, together with the sort codes and account numbers used for Direct Debit payments all could have been accessed by hackers, it said.

The firm serves more than 1.7 million people, but has not revealed how many of those are affected.

A free 12-month monitoring service to help protect customers from fraud and automatically alert them if a credit arrangement has been set up in their name has been offered to those affected.

A spokesman for the company said: "I can confirm that the notification letters some of your listeners have received are genuine and that we have taken expert advice on the package that has been put in place to support them."

Andy Willicott, managing director of South Staffs Water, has previously apologised to those affected, saying that he understood the firm's responsibilities to keep customers' data safe.