It is a sample rejection letter from school, If they are not able to execute fundraising campaign that time. School give time for execution and give different ideas for funding campaign according to school policies. Sample format of refusal  letter is below.You can use this according to your need.

Regret Letter from School to Execution of Fundraising Drive

Dear Mr, Waseem Chawla,

This is to inform you that we, at Lahore Alma, would not be able to make any monetary contribution this year, as we have already made a commitment to support another institute.

However, we shall continue to support your cause in the future.

Regards,
Saleha Usman
Coordinator Senior School.

Rejection Letter from School Regarding Charity Drive

The Marketing Department.
ABC Organization

Dear Ms Hina,
Thank you for keeping us involved in your activities, allow me to appreciate the work your organization is doing. We at________ believe in the value of community service, and teach our students to pursue it passionately.

Unfortunately, our school is currently working with the Bali Memorial Trust, to raise funds for victims of the floods around Pakistan. At this time, we will be unable to offer our support because our school branches are heavily involved in the current campaign. Furthermore,________ encourages students to brainstorm creative techniques for raising funds outside of selling items. Our children generally do not sell tickets for charity, they run activities and donation campaigns that involve the rest of our student and staff body.

Please feel free to get in touch with me new campaigns in the future. I am always open to new possibilities.

Kind regards,

Zaberia Tahir