NORTH ADAMS — The city charges that Charter Communications is guilty of "a pattern of neglect" and should pay more than $500,000 for not following through with promised fiber upgrades in the city.

Those allegations were part of a letter written by North Adams Mayor Thomas Bernard to the parent company of Spectrum, which provides cable service residents in the city and across much of the Berkshires.

The letter, dated Sept. 5, outlines a number of alleged violations of the city's contract with the company.

"Charter Communications has demonstrated a pattern of neglect and non-responsiveness to the issuing authority, its designees, the City, the access corporation, and subscribers," Bernard wrote.

A spokesman for the company did not comment on specific allegations on Thursday but confirmed that Charter will submit a formal response by the Oct. 5 deadline. If the city and Charter cannot resolve the dispute, it could result in litigation.

The alleged violations largely center on the company's treatment of local public, educational and government access channels — including the failure to install contractually required fiber lines for Northern Berkshire Community Television.

The 10-year contract was signed in 2014 between the city and Time Warner Cable, which has since been purchased by Charter Communications.

At a May 31 public hearing, city officials and members of the public blasted Charter Communications officials and representatives with a number of grievances, ranging from the inability to receive public access channels to poor picture quality.

The letter calls out Charter Communications for failing to provide NBCT with 30 days of written notice before it relocated the channels from the teens to the 1300s as part of the company's transition to an all-digital transition earlier this year. The letter requests that NBCT be paid $2,000 for this infraction. Under the contract, Charter agreed to install fiber lines between the NBCT headquarters on Union Street and a number of municipal buildings throughout the Northern Berkshires. The transition to the fiber lines was expected to take place on March 16, 2016, but the work has yet to be completed.

Thus, the mayor's letter requests that Charter reimburse NBCT nearly $21,000 for costs it incurred "to both test and make workable (when possible) the return signals from Drury High School and North Adams City Hall."

The letter also suggests that the company compensate the city in an amount "equal to one share of the Charter stock as of the date of this letter" per fiber line for each day that it has not been installed since the originally intended transition date.

The stock price at the market's closing on Sept. 5 was $306.81, and the transition date was 903 days old at the time of the letter, meaning the city was effectively requesting $277,049.43 (and counting) per uncompleted fiber line — one to Drury High School and one to North Adams City Hall.

The second piece of the letter requests a variety of information from the company.

First, the city requests that it verify and provide documentation of its public, education and government access channel payments and Municipal Access and Technology payments, which are contractually required.

"If they're underpaying, there would be additional money due to the city," Bernard said.

The letter also requests a copy of the company's local subscriber complaint log — including date and time of the complaint, the resulting investigation, and way in which it was resolved — from August 31, 2016 to August 31, 2018.

The letter also requests a copy of the log that tracks service outages in the city, for a period from Oct. 1, 2015, to Oct. 1, 2018.

Adam Shanks can be reached at ashanks@berkshireeagle.com, at @EagleAdamShanks on Twitter, or 413-629-4517.