TalkTalk, a British communications provider, has been hacked, with the chief executive saying on Friday that a ransom demand had been received from the hackers that claimed responsibility for the hack, which saw the theft of personal data for four million customers.

TalkTalk itself offers both cable and fixed-line service in England, and investigators have begun looking into the hack. The hackers were able to gain access to information like credit cards, addresses and dates of birth.

"Yes, we have been contacted, by I don't know whether it's an individual or a group purporting to be the hacker," said Dido Harding, chief executive of TalkTalk, in an interview with the BBC.

It has not been disclosed exactly how much the hackers demanded, or exactly how much data they had stolen. Not only that, but despite the fact that responsibility had been claimed for the hack, it is not certain if the claim was credible.

Even though it's unclear if the claims were true, what is clear is the fact that this is the third hack that TalkTalk has suffered in a matter of only one year. The hack also represents the fact that hackers are increasingly able to break into high-profile companies and steal information about their customers. This data can then be used to demand ransom, holding it until a fee is paid.

TalkTalk's shares fell as much as 11 percent in trading on Friday, Oct. 24, however, by the end of the day they had recovered to be only 2.3 percent down.

Despite the fact that TalkTalk did respond quickly to the data breach, some have criticized the company for discussing the breach publiclly before knowing all the details. The hack, however, comes right before new rules are set to go into place in Europe. These rules say that companies affected by a data breach must inform regulators of the breach within three days of it occurring.