Faulty Samsung J1 and poor customer service

On Saturday 1st August I bought a new Samsung J1 cell phone from Vodacare in Tygervalley. Within a couple of days I realised the speaker was faulty as I could not understand what the caller was saying. I took the phone to Abdul at Vodacom at Old Mutual Head Office (who is really helpful) and he tested the speaker and confirmed it was faulty. I took it back to Vodacare on Thursday 6th (within the 7-day replacement guarantee period) and asked for a replacement Samsung J1. They refused to give me one and insisted that it must be be sent to Vodacom Head Office and then to their repair shop as that is their process. Unfortunately, not having experience of sending phones away for repair, I did not take out my sim card (Ian the sales person assured me that there was no need for the phone to be opened while checking the speaker so I didn't remove the sim card). I have now been without my Samsung J1 for 11 days and whenever I've been back in person to the shop I get passed from pillar to post because the staff don't know what is going on. I just want my sim card back and a new Samsung J1 as a replacement for my faulty one. Is that too much to ask? I'm desperate - I need my phone!