Festival Network, the national company that plans to hold a concert this summer in Ocean Park featuring the Boston Pops, wound up in hot water with Oak Bluffs selectmen this week when a representative asked for permission to expand the concert to a second night.

The request from Rob Scherer drew heat from representatives of several Island nonprofits, who said they are still waiting for crucial information from event organizers about the availability of tickets, ticket prices and a list of scheduled performers.

Festival Network has agreed to let three Island charities — the YMCA of Martha’s Vineyard, Vineyard House and the Friends of Oak Bluffs — participate in a ticket sale scheme for the concert, which is scheduled for August 10.

According to the plan, each group will be allowed to buy between 300 and 350 reserve location seats at face value. The groups can then build a package around those tickets which might include a meal or other entertainment, sell them at a higher price and keep the difference for fund-raising purposes.

But several nonprofit spokesmen on Tuesday said they are still waiting for basic information from Festival Network.

“The communication has been terrible. We don’t feel this is a partnership at all,” said Christine Todd, fund-raising director for the YMCA. “Day after day we have no information about these tickets, and day after day we are losing momentum to build an event around these tickets.”

Ms. Todd said the three nonprofits found out about the proposal for a second night just hours before Tuesday’s selectmen meeting. She said she worried that an expanded event would only raise new questions about the availability and cost of tickets.

“We already have such a vague notion of what this event is, and now they are here asking for a second night . . . will it push this back a few weeks more? We have stood by this event and tried to make it work, and we still want it to work, but this might become a logistical nightmare,” she said.

John Early, a board member for Vineyard House, was equally blunt.

“We have been treated with disrespect by Festival Network. We look like a chain of fools here,” he said.

Ms. Todd said the nonprofits were given a preliminary quote of $135 per ticket. The general admission price of a ticket last year was $45, with a $5.50 surcharge. In addition to the Boston Pops, that concert featured performances by Natalie Cole, Branford Marsalis and several other acts.

Mr. Scherer said he understands the concerns, but he said Festival is still waiting for several performers to give a final commitment to the concert; until that happens organizers will not be able to release detailed information.

“It’s very frustrating waiting for talent, that is the hardest thing to pin down in this business. We’re dealing with people who can afford to turn down an offer [to do a concert] . . . all I can say is I’m sorry,” he said.

He said Festival is asking for a second night to accommodate a performance by a “legendary, Grammy award-winning” performer who could not make the first night’s performance, although he would not identify the performer.

But selectmen were less interested in the identify of the performer than they were in the waiting Island charities. They demanded that Festival provide as much detailed information as possible by the end of this week.

“If this thing isn’t worked out quickly, then maybe [we take] it off the table,” selectman Roger Wey said. “We are providing the space on one of the busiest nights of the summer. I think these nonprofits deserve to have the details, and we need to know what’s going on.”

Another concern was whether a concert on the second night might conflict with a planned fund-raising event for Hospice of Martha’s Vineyard.

“We’ve talked about ways to dovetail this, but clearly it’s very complicated,” said Terre Young, executive director for hospice. “I worry that having both events on the same night would have a negative effect on both events, there are only so many volunteers available . . . I just hope we can figure this out.”

Judy Williamson, who volunteers for both hospice and the Friends of Oak Bluffs, said she worried the expanded concert would foster unwanted competition among nonprofits.

“When I first found out today they plan to cross over to Monday I thought ‘Oh my God, that’s hospice’s day [to fund-raise] . . . I don’t think anyone intends it, but this does bring a competition between the nonprofits. It’s not something any of us want.”

Selectmen unanimously agreed to send a letter to Festival Network demanding detailed information about the tickets and concert as soon as possible.

Selectman Kerry Scott, who pushed for town counsel to research legal questions about the concert and the use of Ocean Park back in April, said she was shocked people were still waiting for information about the concert. She cited Ronald H. Rappaport’s legal opinion about the concert, which among other things concluded that concert organizers must demonstrate a clear public benefit to justify using Ocean Park for the event.

Ms. Scott said the public benefit remains in doubt, especially in light of the continued lack of information.

“[The nonprofits] aren’t the only parties in this chain of fools. We asked for this information back in March and we’re still waiting . . . to be at this late date and not even know how much these tickets will cost is shocking to me. As far as I’m concerned that public benefit has fallen flat on its face,” she said.