NI Water overwhelmed by 1m contacts from customers
Northern Ireland Water (NIW) has apologised to customers for its handling of the recent water shortage.
The company's director of customer service, Liam Mulholland, told a Stormont committee that the scale of the problem had taken them by surprise.
He said more than one million contacts were received from members of the public at the height of the crisis.
Former chief executive Laurence Mackenzie resigned after mounting criticism of the company's response.
He officially leaves office on Friday and was due to appear before the Northern Ireland Assembly Committee for Regional Development which is hearing evidence about the crisis.
His decision not to attend was criticised by the chair of the committee Fred Cobain.
"This is a huge issue, not just for this committee and the Assembly, but for the thousands of people who have suffered," he said.
"He has a responsibility to those people. As far as we are concerned he should have been here and he is not."
A number of officials from the government-owned company did give evidence at the Stormont committee on Thursday.
Mr Mulholland said the company had received 6,000 calls on Boxing Day and that the system had been "quite simply overwhelmed".
"We have some 200 lines coming into our call centre. If we look at 27, 28, 29 of December there is something in the region of over 600,000 attempted calls into our business," he said.
"It is no wonder therefore that you see the levels of anger and frustration amongst our customers."
"There is nothing more frustrating than trying to get through to a call centre that you can't through to."
SDLP committee member Conall McDevitt said that on 28 December, there were 403,000 call attempts to the NI Water call centre, of which 3,334 were answered.
Mr McDevitt described that as an "abysmal performance".
It was also revealed that during the crisis, the company received 10,000 e-mails and its website received almost 500,000 visits.
The company's director of customer services, Sara Venning, told the committee that prior to Christmas she believed sufficient preparations had been made for the impending thaw.
"I felt my plans were sufficient to get us through," she said.
The Stormont minister responsible for NIW has said the former chief executive would not receive a "golden handshake" package.
Regional Development Minister Conor Murphy said he is seeking legal advice over Mr MacKenzie's minimum entitlement terms.
Mr Murphy estimated the figure to be under £100,000 and said it would be made public.
Mr Murphy also stressed that he wanted assurances that Mr MacKenzie would remain "available to assist the review" into the crisis.
The review which is being carried out by the Utilities Regulator is due in February, and its terms of reference are expected to be made public on Thursday.
Mr MacKenzie's resignation had been widely predicted in the aftermath of the crisis.
The company has appointed its current director of engineering, Trevor Haslett, as the interim successor to Mr MacKenzie.