Leading credit data firm Experian has received a number of class actions in relation to the breach of T-Mobile US customer data at one of its servers in September.

The legal action relates to a breach that exposed the personal data of 15m people who had applied for services with T-Mobile in the US, in addition to affected customers who applied for T-Mobile US services over a two year period, from September 1 2013 to September 16th 2015.

Experian said the breach was an isolated incident affecting a single client, and that its consumer credit division and payment details were not involved.

It is working with both US and domestic and international law enforcement agencies to investigate the matter.