Poor service/no feedback/bad attitude

I opened a vodacom contract for galaxy s7. With the phone you can chose between a wireless charger or bluetooth speaker. I chose the charger and afterwards I was told they dont have stock but should have stock by the end of the week. I struggled for 3 days with endless phone calls to finish the porting of my number and another 2 days to activate caller identity. Its been over 3 weeks now and still dont have my wireless charger. They dont have stock and cant tell me when they will get stock in. So I decided to change to bluetooth speaker just to get the deal done. First they told me I must phone customer care to change it. Customer care said the branch must change it themselve. Been to the branch again, and after waiting for 30min for the consultant, I asked her to change it and I was told she cant, the deal is already done and she ignored me and went on with other customers. They dont want to give their manager's number either. I have heard numerous complaints about this branch and thought I would still give them a chance. But this service is absolutely pathetic. And according to me the contract is still invalid because I havent received the total package. How can it be resolve