Central Maine Power’s CEO Doug Herling, appeared in a video tweet on Aug. 13, apologizing for CMP’s response to customers' concerns after the new billing system was put in place last October.

It is the first apology CMP has made since the power outage in October.

“When you raised concerns, we didn’t respond as well as we should have, and we’re very sorry about that. You deserve better," Herling states in the video.

The video states CMP has expanded its customer service team, made technology upgrades and “is working hard to respond to each concern that has been raised.”

Herling became CEO in January this year, replacing Sara Burns.

The ad said it was paid for by CMP shareholders.

Maine Public Utilities Commission's investigation into the issues is ongoing. CMP also faces a class action lawsuit based on high bills and customer service complaints.

On Aug. 7, the PUC confirmed a new rate investigation it ordered July 24. The investigation is based on evidence presented by a group of ratepayers that CMP shareholders may have received excessive returns on their investment since the last round of rate setting. Based on its own calculation, the PUC found the returns on investment were significantly higher than permitted in 2016 and 2017. CMP spokesman Gail Rice said in July that CMP was cooperating with the order.