Samsung Galaxy Watch5 *******

I upgraded my cellphone to a Samsung Galaxy on 3 August 2023 and received a Samsung Galaxy Watch5 as an add-on "gift". From the start, the battery of the watch lasted no more than 5 hours. I went back to the Vodacom store in Somerset West Mall on 11 August 2023, and it was sent away for "repairs". Thet never contacted me to collect it and I went there on 27 August 2023 and it was waiting for me.. On 28 August the battery lasted 7 hours. Today, 29/8, after having charged it through the night, there is 48% battery life left after 3 1/2 hours with it NOT even connected via Bluetooth to my phone. The Vodacom shop told me to bring it back again to be sent away again! I do not want it to be sent back again! What can I do to have it replaced?