Unpaid internships need to meet a very specific criteria to be legal:

• The internship, even though it includes actual operation of the facilities of the employer, is similar to training which would be given in an educational environment.

• The experience is for the benefit of the intern.

• The intern does not displace regular employees but works under close supervision of existing staff.

• The employer providing the training derives no immediate advantage from the activities of the intern and on occasion its operations may actually be impeded.

• There is no guarantee of a job at the conclusion of the internship.

• Both parties understand that the intern is not entitled to wages for the internship.

The bold is my emphasis. To me, asking you to fundraise sounds like a violation of these rules. If you were to shadow an employee while they do fundraising, then that would be okay, but the company can't ask you to do things that they would otherwise hire someone to do.