I need to see this and do something about it.

Good day.My name is Khanyisa Kula,I bought a phone last year in December 2019 from Vodacom (Madeira street) in Mthatha and it started giving me problems in May this year(2020),I took it to Vodacom for repairs,It took me two weeks to get my phone back and it came back with the same problem I.e freezing,switches itself off while using it, not charging sometimes and when I tried to switch it off,it wrote Samsung on the screen for a couple of hours then eventually switched itself off. I then took it to Vodacom again n they sent it to advance repair center and have me waited for two weeks again.it came back with the same problems again. I went to Vodacom and spoke with the manager and I was advised to call repair center and ask them for an exchange but they told me that they can't change the phone and all they going to do is to fix it free for me because it is still under warranty.I went to the store manager again for help and he told me to bring the box,charge earphones and I brought everything and I was promised that they will send it to repair center and write an email. After two weeks waiting for exchange,I got an SMS from Vodacom that I must go and pick up my old phone from Vodacom and I failed to pick it up,it will become a property of Vodacom.I went to the store to pick up my phone and it is still doing the same thing. I'm very disappointed with Vodacom,I have been with them since 2003 and I didn't think that I would get such treatment.please help me to resolve this matter.