Kieran McCarthy MLA said: “This is just the latest in a line of errors that have been caused by NI Water. It was only last year that NI Water announced that it had made a mistake in calculating water costs meaning that household bills would be £30 higher.
“NI Water must improve their billing services immediately to ensure that no more errors occur. If these types of mistakes are not eradicated then some people may lose confidence in the company.
“With the current economic downturn I am sure that businesses did not need the problem of being overcharged, money that could have been better spent on shoring up their businesses.”