Refund

This year some time I took a package on an MTN shesha deal Promo: 600GB at R399 PM* and on the second of September I returned the router as I had moved in an apartment which has Wi-fi with expectation to get my refund from since the 02 Sept 25 up until now I had not gotten my refund for month which I had not used the Wi-fi instead I got a statement emailed to me that I'm owing R25 which I do not know what is it for??? When I went to MTN Rosebank I was assisted by a guy called Sonwabisile who assured me that my cancellation was being processed and I should get my refund. MTN is the most pathetic service provider which I will not recommend to anyone else every month I'm being emailed statements that I'm owing R25 which I will not pay it since they refused with my R399 which is due to me, when you signed up with them you are being told to pay double subscription now I know it is for this reason to **** people up and refusing to pay them their refund... each time I do inquiries on this matter at rosebank branch I'm being told to call the call centre as they do not deal with refunds as a customer I'm being told to phone myself.