THE MBTA IS STILL NOT SATISFIED with the performance of the private company overseeing its paratransit dispatch service, and sources say the authority is trying to figure out a way to sever ties and hire a new vendor.

Global Contact Services was hired in 2016 to operate a centralized call and control center for the MBTA’s paratransit service, which provides rides to people with disabilities. The T had been operating three call centers and wanted to consolidate them into one to provide efficiencies and save an estimated $12 million annually.

Two of the call centers have been merged. Consolidation of the third was supposed to happen July 1, but was postponed until Oct. 1 and then again until at least Nov. 1 because of persistent service quality issues. As of this week, the third call center still has not been consolidated. At one point, the T hired a consulting firm to evaluate Global’s operations and the firm’s report gave Global poor marks in just about every category.

Sources say the T has decided to move on, but has to tread carefully because the transit authority can’t just fire Global and hire a replacement firm. The sources say the T needs Global and the existing operator of the third call center to remain in place serving customers while a new company is hired and brought up to speed.

MBTA General Manager Luis Ramirez indicated after Monday’s meeting of the Fiscal and Management Control Board that nothing has changed with Global. “Everything’s the same,” he said. “We continue to work with the contractor to make sure we’re improving services, and we continue to make sure that our ridership is being given the best service possible.”

A T spokesman issued an almost identical statement. Officials at Global could not be reached for comment.

The paratransit consolidation, and the savings it was expected to generate, played a minor role in the T’s budget deliberations for the current year. T officials in recent years have tried to run the authority using just the money they receive from the state sales tax and revenues they generate on their own from advertising and parking. They have tried to use a $187 million annual state budget appropriation just for longer-term capital investments. If the expected savings from the paratransit consolidation fail to materialize ($1 million forecast for this year), there will be less money for capital investments.

Bruce Mohl oversees the production of content and edits reports, along with carrying out his own reporting with a particular focus on transportation, energy, and climate issues. He previously worked...