DStv - debited more than I allowed

DStv - double debited more than I allowed and keep saying they've escalated the matter. It's been almost a month now and nothing has happened...no refund! I cancelled the debit but someone (allegedly) from DStv contacted me asking for my banking details. They couldn't provide any credentials because their system was allegedly down and said they would call me back...no call since last week. It's time to cancel DStv and stream instead!