PARATRANSIT ADVOCATES said on Monday that the MBTA’s new centralized call center is off to a rocky start, and agency officials acknowledged some glitches as the service has been rolled out.

The T is trying to consolidate three call centers into one, with the goal of saving an estimated $7 million a year in operating costs. So far, only two of the regional call centers have been consolidated.

Marilyn Villers, executive director of Massachusetts Senior Action Council, told the T’s Fiscal and Management Control Board that many of her members have reported problems with poorly trained dispatchers and late pickups. She said the T’s private vendor also appears to be experiencing technology problems.

“They aren’t on top of it yet,” she said. “The word among RIDE customers is that you have to be careful because you might get stranded.”

Marilyn McNabb, a Boston resident, recounted a problem she had with a poorly air-conditioned van and her difficulty in communicating with dispatch staff. She said the operator of the call center is not paying dispatchers enough, so a lot of the workers at the regional call centers are not moving over. “We lost a lot of real good dispatchers,” she said.

Several members of the Fiscal and Management Control Board raised concerns about the problems and asked Brian Shortsleeve, the chief administrator and acting general manager of the T, for an explanation. He acknowledged some problems during the transition to a centralized call center.

“We know exactly what needs to be addressed,” Shortsleeve said. “I am confident we’re going to see improvement over the next four to eight weeks.”

Joseph Aiello, chair of the T board, asked T officials to give the board a weekly update on progress.