Vodacom not giving back my money..

Vodacom offered me a router in 2017 and when they delivered, they wrongfully delivered 3 routers instead of 1. They continued to charge me for the 3 routers. I called and they investigated and found that indeed I did not agree to 3 routers. In August 2018 they collected the routers and were supposed to refund me for the two routers which I returned. To this date, Vodacom has not refunded me. Every time I call Vodacom I get a different person on the phone and the details are never recorded correctly and I have to keep on repeating myself. I am not getting my refund instead Vodacom will drop me calls that I owe them. I am so tired of following up with Vodacom. In October they took about R2841.28 from my bank account, supposedly for pre-mature cancellation of the routers. They wanted to return my money after 7 days - whilst they were not supposed to have taken it in the first place and inconveniencing me in the process. I later reversed the debit. In October I also cancelled my air-time contract which had already ended, and still they failed to this, I had to call and do it again. Vodacom must refund me more than R5000 which is due to me and they are not doing this and they get their calculations incorrectly. All I want from Vodacom is my money back, nothing else, I will even switch to another network.