Returning an Online Phone Purchase Seems to be a mission

I bought a phone online for cash on the 28 February 2025 and was delivered on the 4th March 2025 order number ***. The phone seems to be faulty as it keeps switching off. I have been trying to return it but I keep getting the run around from vodacom, being referred from one department to another. I even went to the store in Fourways Mall and I was told they don’t work with online shop purchases. Customer service online (Boitumelo Mokwena) said I should email *** but haven’t gotten any response. The store told me I have 14 days to return the phone. Not sure how to proceed. Please urgently assist.