Ian Scott, Bob Tait and Alex McQuade say they fear the decision will mean cuts and closures for local cultural, sport and leisure services - and councillors need to explain their decision properly.
Their complaint also points out that key management at Falkirk Trust were not consulted about the decision which will have a massive impact on them.
The former Trustees - who were board members from 2011-2017 - have also written to Audit Scotland with their concerns that the decision will mean a loss of £1 million every year in rates relief.
At the time of writing, Falkirk Council had not replied to the complaint.
Audit Scotland has said that it will review the decision as part of a Best Value review of the council, which will get underway soon with the results published by early next year.
However, the complaint's authors are worried that by that time any damage will have been done.
And they say that despite raising their fears repeatedly with councillors they have still not had answers.
Ian Scott said: "It has been a number of weeks now since we raised our concerns with the Council Leader and it looks to us that the administration has decided to lie low in the hope that it will blow over. It will not.
"It is sad to see that having failed to consult anybody before they made this crazy decision they are also refusing to explain their actions to the people who elected them.
"This is arbitrary power at its worst."
The formal complaint to the council highlighted the lack of consultation with anyone who was likely to be affected by the decision.
It stated: "Members of the board of the Community Trust, people in leadership roles in sports, culture leisure and arts, participating members of the public, external bodies involved with these areas at national level and other stakeholders like OSCR were ignored in direct opposition to the council’s expressed intention to listen and consult when big decisions were under
The authors of the letter say councillors were presented with a paper by the Chief Executive pointing out the "real and potential financial damage likely to be incurrred".
They added: "We believe that any rational reading of this advice would have led to a different conclusion."
Recently, a proposal by the chief executive shows that the Trust will not return as one entity.
The complaint stated: "The impact on the staff has been considerable especially those in key management positions.
"This has been exacerbated by the subsequent proposals regarding the splitting up of the services and tacking them on to existing departments.
"There are already serious consequences with staff indicating their intention to leave their posts."
SNP and Conservative councillors supported the change but at the time writing had not commented.
The Labour group says the Trust has done everything it was asked to do, cutting the subsidy it needed and substantially increasing customer numbers.
Group leader Robert Bissett said: "The council is already subject to severe budget cuts and now this ludicrous decision means we have now lost £1m in rates relief every year from now on."