The telecom provider Sure has been fined £80,000 for data breaches in last year’s directory.
The Office of the Data Protection Authority took action after Sure told the regulator there had been a “small number of entries” that were incorrect.
An investigation by the ODPA found 216 complaints had been made to the company relating to 244 telephone numbers.
Some of these included the numbers of ex-directory islanders being published.
Sure identified 19 customers that were at risk of “potential material harm” as a result of the mistake.
The company said it was “disappointed” by the ODPA’s ruling which it said was in parts “factually incorrect” and based on a “flawed and unfair investigation”.
“This included a lack of full disclosure about the specific matters of concern to the ODPA, which in turn made it difficult for us to participate meaningfully with the process,” Sure said.
Source: BBC News