Connecticut’s attorney general says he’s “outraged” at the problems M&T Bank customers encountered when the bank merged its systems and those of newly-acquired People’s United Bank last week.

Attorney General William Tong issued a letter to M&T Bank asking executives of the Buffalo bank, which bought Bridgeport-based People’s United last year for $8.3 billion, for a meeting and “dedicated high-level individual to serve as our contact to expedite resolution of these serious complaints.”

M&T combined accounts of People’s United customers and its own customers over Labor Day weekend, but wound up accidentally locking many out of their accounts. Lines of frustrated were reported at local branches.

The Hartford Courant reported that many customers faced three-hour waits to get questions answered by the bank’s customer service phone line.

“I share your customers’ outrage at the serious lack of preparation for this conversion. M&T’s poor planning cost Connecticut customers timely access to their banking records, their bill pay systems, and their money. Connecticut customers wasted hours of time on hold and in branches trying to sort out problems that should have been addressed prior to the conversion. Should Connecticut consumers continue to experience extended gaps in customer service, my office will not hesitate to use the full extent of our authority to protect families and businesses,” Tong’s letter said.

In an interview with the Courant, M&T Executive Vice President of Community Markets Mike Keegan said the bank “has some work to do,” but promised customers “we will get it right.”

In his letter to M&T, Tong reminded bank executives that he and other local officials had pledged to watch the lender “closely ensure that your actions matched your written commitments to local jobs and Connecticut communities” after a controversy over how the bank planned to use the former People’s United headquarters building in Bridgeport.