Incorrect diagnosis by staff

I took both the D5 evo pc board and power supply unit (psu) to Stafix for testing as the battery was not charging. I was told the pc board was faulty but the psu was working fine. I was advised to go to centurion Boksburg for repairs and replacement. Upon arrival at centurion Boksburg on 22 Aug 2024 I was assisted by female worker at reception who tested both parts and informed me that the power supply unit was faulty but pc board was working. This is contrary to the advice by Stafix. She did indicate that she had never tested the power supply unit before but I didn’t pay attention to it. I then paid R512 for a replacement psu as I had no reason to doubt her advice. I asked her if she was certain that there was nothing wrong with the pc board to which she responded positively. To my shock When I got home, the battery was still not charging. I’m convinced that she incorrectly diagnosed the problem leading me to buy a psu that was not faulty. I’m further convinced that the diagnosis by Stafix was correct. I’m highly disappointed. Please ensure that all your staff is skilled and knowledgeable in all your products to avoid customers incurring unnecessary costs.