Bad after sales service DDD Appliances

We got a quote for a 5KVA solar system at DDD appliances. They told us everything is guaranteed even their services. The system was fine for about one month. Then the trouble started. A fuse blown and we phoned them and they only came out three days later. There is no power in our house if the inverter trip. Luckily I know something about power and connect the power again on the municipal power. We would have been without power for three days. They just reconnected the inverter and after a while it tripped again. So we phoned them al lot of times and they could not sort the problem out. We told them to send the inverter in to the company as it is still under guarantee. Two weeks later, they told us that the company say there is nothing wrong with the inverter. We were away on leave for ten days and told them the monday after we got back to install the inverter again. After two and a half weeks they came and put back the inverter. Needless to say, we still have the problem. He did not give us the guarantees at all . I asked it from him a few times without any luck. Dennis told me to install another solar panel. He was sure that that will resolve the problem. I told him that I am not going to pay for it if it does not solve the problem. So his electrician came and install another panel. They disconnected half of our house from the inverter. They told us the batteries must first charge full and they were sure it was going to work then. They said the batteries will be charged in 48 hours. The system could not even give power to half of my house. The load on the inverter is only 17% and if we put an aircon on, the inverter cuts out. I was fedup for this bad after sale service and told him to come and take this system out and give back my R56 000,00. He refused to do that. I told him then he must fix this system. After that, he does not answer his phone. When we phoned the electrician he said that Dennis said that he will not come to sort out our problems anymore. I am sure they do not know how to solve the problem. That is the after sales service we get for a system they said was guaranteed for years.