DSTV refusing to downgrade my package!

On 27/2 I spoke to Deen Ryan to downgrade my DSTV package. He assured me this was done and that from end March my monthly premium would be R340 odd, rather than R1100 odd. This actually happened, but then on 26/4 I saw that DSTV planned a debit order for R1109 for end April again. I called and spoke to Lusanda Fumele who argued that the downgrade was never done. She would do it for me and assured me my payment end April would be R400 odd. It was R1109 again! What must I do to get DSTV to downgrade my package as requested, or should I just cancel completely?