Manager (or anybody for that matter) do not phone back when requested

Been waiting to get a refund that their staff member Musa promised I would get. Now my emails, online messages etc all get ignored EXCEPT on their Facebook page where they reply to my messages promising a manager will call me.......I'm still waiting and it's nearly 4 months of begging.......disgusting considering i supported them when they first started, passed them many clients and never given then problems. Be interesting to see if they both to reply to me on this platform. Hope so cause i won't stop....getting ready.........