Virgin Media is to pay a total of €421,000 to 24,000 customers over a transparency issue in 2016 and 2017, following a settlement agreement with Comreg.
In 2018 the regulator found that the company had failed to comply with rules governing the presentation and charging of extra charges to some of its customers.
The charges related to issues like late payments and unpaid direct debits.
Comreg was particularly concerned with the transparency and accessibility of the contractual provisions relating to those tariffs.
The customers are due to get the payments by September 1.
Virgin Media has also committed to publishing a price list in a prominent location on its website and provide a direct link to it from the homepage.
It has also agreed to amend the terms and conditions it issues to all customers to include a link to its price list.
Virgin Media is also to provide a clear description and details of the additional charges that may apply to a customer.
In a statement, Virgin Media said it strongly believes that it delivers confidence and transparency across all its customer communications.
"Comreg's notification takes account of measures that Virgin Media has already agreed to close out this dispute and these measures are not an admission of any liability on our part," it said.
"It should also be noted that Comreg's quarterly consumer line statistics report show that Virgin Media has the lowest number of customer complaints for three years running."