SAMSUNG - SHODDY SERVICE

We purchased a Samsung dishwasher about 5 years ago - Model DW-FN320T. It has hardly been used. It gave a H4 error. After checking the trouble shooting in the user manual and on their website there was no such error code to be found. I phoned Samsung but they could not tell me what the error code was and insisted an approved repairer would have to look at it. When the repairer contacted me they wanted a deposit of R450.00 before they sent anyone out. I understand the machine is out of warranty but found the call out fee to be high and the request quite extraordinary. I asked what the H4 error code referred to but they too were unable to provide an answer. Because I don't use the machine often, we decided to just leave it for the time being. Bergens Appliance Repairs in Boksburg has a great reputation and I contacted them. At no cost, they collected the dishwasher. They called to say they suspected it was the PC Board that they had to order it from Cape Town. It took a few weeks but Simone kept me updated. After they installed the PC board it still gave the same error. They spoke to various technicians, replaced the door mechanism, tried a different aqua-hose that was suggested but still the error remains. They were very apologetic but they are unable to establish what the fault is. Simone tried calling a consultant at Samsung but was told she is very busy and would call her back. She never did. The machine has been returned at no charge at all. I called Samsung (***)again - Spoke to Lauren on 26 June - *** and after telling her the whole experience she said the consultant would contact me within 24 / 48 hours. Today, 29 June I called again and Kholoselo assured me someone would definitely call me today. Still waiting in anticipation. Why can nobody tell me what this H4 error code is? Is it because nobody knows? I am prepared to pay for a repair but want to know whats broken first. By the way Covid is no excuse for the shoddy service....