Customers caught up in a state-run electricity provider’s multimillion-dollar payment bungle could be waiting months to get their money back.

Synergy will carry out a major refund operation after it failed to notice that $40 million had poured into more than 170,000 closed accounts between 2009 and 2025.

WATCH THE VIDEO ABOVE: WA’s energy minister blasts Synergy over billing bungle.

WA ’s monopoly utility apologised for the scandal , with state Energy Minister Amber-Jade Sanderson taking aim on Monday.

“This is a significant issue and disappointing and unacceptable,” Sanderson said.

“The government expects Synergy to act swiftly to repay customers and provide clear and transparent information to the public.”

Synergy allowed close to 174,000 business and residential customers to co

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