M-kopa not refunding me.

I strongly feel that M-kopa is unprofessional when it comes to the service to their customers..i returned one off their smartphones when i no longer had the finance to pay after job loss..And they told me they will refund my device deposit in 48 hours and now it has been more than 4 days..when i enquire they give me the run around asking all sorts of weird information request and not giving me a straight response on why they have not refunded me as yet...So to me its clear they dont want to refund me..They making useless excuses....