Jeremy Hackett, the QS at Schofield Lothian who led the campaign to hold the meeting, said that he had already started raising pledges of support to pay for expert advice on whether the RICS' decision was legally watertight.
He also wants counsel to investigate the legality of the original RICS decision, made last May, to increase the membership fee 32%.
Hackett said he had received undertakings from backers to contribute £10,000 towards the estimated £20,000 cost of legal advice.
Hackett reiterated his determination to carry on his fight (see opinion below). He said: "I have received promises [for cash] from many people. We are not lying down on this issue."
Hackett said that members who were discontented had three options. They could resign, delay payment of subscriptions until just before the final deadline on 31 March, or withhold payment and wait and see if they were thrown out of the institution.
We are not lying down on this issue
Hackett called on large QS firms to reconsider whether to pay the subscriptions of employees.
He suggested they should pay only part and let staff decide whether to pay the rest. He said: "This would concentrate people's minds over whether the RICS offers value for money and is relevant to the way members earn their living."
A RICS spokesperson said that the decision not to hold the EGM had been made on cost grounds.
The spokesperson said: "Hackett is obviously a very determined man and will do whatever he does. We cannot control him."
RICS president Nick Brooke said last week that Hackett's concerns would be dealt with as part of his review. This will look at three issues: communication, infrastructure and governance.