Facebook does have a feature called "Charitable Giving on Facebook". 

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What does it do?  Nonprofits can raise money directly from their Facebook page with the Donate button. The Donate button is a quick way for supporters to donate to an organization without leaving their Facebook. Facebook users are able to add the button to their page and posts for supporters to contribute through a one-page form on Facebook. 
  • To find out more about Charitable Giving on Facebook, click here.
  • For the Charitable Giving FAQ, click here 
Can gifts be transferred from Facebook to Sphere? Due to Facebook being a third-party vendor and the feature being owned by Facebook, it is not possible to transfer the funds. Sphere only utilizes the Facebook plug-in to allow supporters to share pages via their Facebook.

How can I receive the donations? There are 2 possible ways you'll receive your donations. The method in which you receive donations will depend on how you're registered.
click here for more information.
  1. When a nonprofit that is registered with Facebook Payments has at least $100 in donations, it becomes eligible for a bi-weekly payout. The payout is a wire transfer (ACH/direct deposit) to the organization’s bank account. If a nonprofit's total donations hasn't reached $100, the funds will roll over until the amount reaches at least $100.
  2. If the nonprofit isn't registered with Facebook Payments, any donations it receives are distributed through the Network for Good‘s donor advised fund. Donations are generally distributed a month and a half after the last day of the month in which the donation was made. For example, a donation made in January will be paid to the nonprofit on March 15.
    If a nonprofit is registered with the Network for Good, it can apply to receive funds via electronic transfer (EFT). If a nonprofit hasn't signed up for EFT, it'll receive its donations via check.
Note: We provide links to third-party websites in an effort to help you resolve your issue . We are not responsible for the information on third-party websites and we cannot assist with implementing resolutions from these websites. 

How can I prevent further donations from going through Facebook? Due to Facebook being a third-party vendor and the feature being owned by Facebook, it is out of the scope of Sphere support to prevent the button from appearing on Facebook shared posts. However, your event admins can educate their supporters about the Facebook donate feature and to avoid the enabling of it on shared event/fundraising page posts through verbiage on the event's website or event email.