Samsung Kollonade bad service

Samsung Kollonade last year July fixed my phone Samsung A52 Screen so during this month screen started to show colors then dark, took the phone to Samsung Hillcrest they reported that the phone was tempered so they can't help me I told them Samsung Kollonade did fix it last year, so took phone back to Kollonade they told be that the screen is on warranty but since it was tempered they can't help I explain to them I didn't took my phone to any shop beside Samsung Hillcrest and Kollonade so they said pay R3000 again, I called head office to report this case they said they can't intervene, my phone was new that's why I preferred to take it straight to Samsung and pay R3000 then to go to any shop. Bad service