I need help urgently

Admin i Need Advise/ Help : I bought cellphone at Mdantsane Cash Crusade last year in July 2020 , & was working till June 2021. I returned it since it's under guarantee, was told to wait for 21 days and on 25 June was told it has not returned from workshop. They ask for R800 maintenance fee , when I told them to give Me back my cellphone, was told to wait for 7 days then was told to wait another week they keep on stalling. Today they said I mus wait for a call from them, with no time frame. My number is ***