Penalized for DSTVs mistake!!!!!!!

So DStv disconnects me for their mistake. I logged a complaint with them. They credited my account twice with a reward I won and then suddenly decide that it was incorrect and now bills me R1680. In this day with covid who can afford such amounts. I paid R800 already was connected and now I am disconnected again. No one calls me nothing. I want this amount waivered and a manager to call me asap