In the first instance you should raise your concerns with the charity trustees, preferably by writing to them. They need to know if their choice of fundraising raises concerns with the public.
It is not within the Commission's our jurisdiction to consider complaints about charity fundraising if the charity trustees act within the law and the provisions of the charity’s governing document. If you have taken up a complaint or raised a concern with a charity about their method of fundraising and you have not had a satisfactory response, then you can bring the matter to the Fundraising Standards Board (FRSB).
The FRSB deals with public complaints about fundraising activity. They do not deal with general complaints about a charity, such as the services they provide, their administrative costs or charity shop issues. You can find out more about how to complain at the FRSB website.