False phone diagnosis of phone fault to not pay warranty

I recently took my Samsung A71 to the Grove Samsung store as my phone woudnt switch on after only having it for 6 months. Because the phone is only 6 months old, it is still under warranty unless water damage then doesn't fall under warranty. After several days of my phone being at the store for assessment after phoning and emailing several times for a follow up on the assessment I was told it doesn't fall under warranty that its water damage knowing I never had any liquid near my phone. I declined the quote and had to still pay the assessment fee of R350 which is ridiculous because I took my phone to another technician and there was proof that there wasn't any liquid damage that it was actually the battery that was faulty. My phone should've been fixed by Samsung under warranty. Absolutely poor service. Couldn't send me proof of damage of my phone. Quoted me R6000 to fix the phone where in fact it cost much less and several other places. Total ******* of something that was a fault with phone I refuse to buy a Samsung product in my life again. If its under warranty fix it.