Vodacom sandton city repair refusing to refund me R1,814.19 for a phone they failed to fix

I took my cellphone to Vodacom sandton city repair on Tuesday, 07 2021 to be repaired. The was not switching on. They charged me R1,814.19 which I paid on the same day. I went to collect the phone on Friday, 10 December 2021 and the battery was flat – it was about 3% charged. I tried to put my pin and got an error that the pin was incorrect. I tried this a couple of times, and eventually the pin worked. The gentleman that I was assisting me, Itumeleng told me that there is a technical issue with the pin on Samsung phones. I took the phone home, and by the time I got home the phone was off. I charged the phone and tried to switch it on, and the phone did not switch on. I took the phone back on Saturday morning, 11 December 2021 and was told to come back on Monday, 13 December 2021. This afternoon I went to the store and waited for more than an hour for my phone and was eventually told that the phone does not want to switch on. I asked them to refund me my money because they did not fix the phone. I told that they had used a replacement part and therefore will not refund me. I was told to send an email to their regional office. I am going to report this to SACC. I have been Vodacom customer for more than 16yrs and this is how they treat me. I want my full refund. The phone was not fixed.