The country's biggest fixed-line telecoms operator, Eircom, revealed yesterday that it will refund €409,000 to 31,562 customers who were overcharged for services including call-answering, barring and diverting.
Individual customers were overcharged by a maximum of around €350, while the smallest amount was under €1. A statement said that the total amount involved was €409,000.
Eircom yesterday blamed a fault in its billing process for the problem, which it discovered after following up a customer complaint about a bill.
The news led to a demand from the Commission for Communications Regulation (ComReg) that Eircom provide it with a full report, outlining how the mistakes arose, why internal safeguards failed and what steps the company had since taken.
"It is disappointing that the largest telecoms company has discovered that there were errors within its billing system," commissioner Ms Isolde Goggin said. "ComReg is seriously concerned that internal systems failed to adequately protect consumers."
She added that recent incidents of telecoms companies overcharging customers had undermined consumer confidence in the accuracy of their billing systems.
Eircom found that 18,291 customers who ordered call answering free of charge were incorrectly billed for the service. They were overcharged by an average of €1.57.
It duplicated charges levied on 13,271 customers between 1992 and June 2004. They were overcharged by an average of €28.62.
Eircom's statement said yesterday that it would refund the money as soon as possible, and pledged that the affected customers would receive the same amount again in credit against their bills.
The company said it regretted the mistakes and wished to apologise to everyone affected by the mistake. A spokeswoman said it would co-operate fully with ComReg's demand for a report on the overcharging incident.
Eircom told the commission when it discovered the problem on July 23rd.
"We would like to assure customers that we have now amended our processes to ensure that call management services are correctly billed," a company statement said.
Labour's spokeswoman on consumer affairs, Ms Kathleen Lynch TD, said it was "remarkable" that systems errors always ended up benefiting the business involved, not the consumer.
"This sort of cavalier approach to charging consumers will only end when those responsible for systematic overcharging are made to pay heavy fines," she said.
Fine Gael's spokesman on communications, Mr Simon Coveney, pointed out that over the last six months, UK-based mobile providers O2 and Vodafone had also admitted overcharging Irish customers.
"Between these three incidents, the amount by which Irish consumers have been ripped off in the last few months is somewhere in the region of €1 million," he said.
