Refund Sisters (환불원정대) is a four-member project girl group formed through MBC's Hangout with Yoo. The members are Lee Hyori (이효리) "Chung Ok" from Fin.K.L and SSAK3, Uhm Jung Hwa (엄정화) "Man Ok", Jessi (제시) "Eun Bi" from Uptown, Lucky J, Unnies, and Hwa Sa "Sil Bi" from MAMAMOO.

The group was created after Lee Hyori's idea of "dream girl group". After she said that in an interview during SSAK3 promotions, the four girls held a meeting to discuss the project. The television host/comedian "Jimi Yoo" (Yoo Jae-Suk) is the group's producer. Auditions for the group's manager role was carried out, with Kim Jong-min and Jung Jae-hyung chosen for the role. They make their debut on October 10, 2020 with their first single "Don't Touch Me". Like the SSAK3 project, all proceeds from Refund Sisters' promotions were donated to charities. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.