What a shame you are unable to complete your fundraising challenge. Please do contact us to let us know so we can inactivate your fundraising page (don't worry, nothing will change except it won't accept any further donations).
We suggest you contact your donors to let them know, and ask them if they would like a refund. In our experience, most people are happy for their donations to be upheld. In the unlikely event that someone would like their donation refunded, you will need to contact the benefitting charity directly and ask them if they are willing to do this. As funds are remitted regularly to our charity partners, and are never banked by SimplyGiving.com first (we simply hold them in escrow), a refund could only be agreed and transacted by the nonprofit.