The parish council is a consultee for the planning process and does not decide whether to grant the planning application or not. They will, when the time comes, submit a comment (or not) on the planning application. It might well be that as the applicant is a councillor, then the council has a policy of not responding. The agenda for meetings has to be published with 3 clear days notice and in that time, things can happen that require items to be withdrawn. Items cannot be added, but they can be withdrawn.
I am not sure what the issue is here - they have not acted illegally. It would seem that you have been inconvenienced as the council pulled an agenda item that was specifically important to you but this is not illegal. Bad manners, maybe.