LG G6 Moisture in USB

I upgraded from Samsung to the LG G6 mid 2017 on very high recommendation from Vodacom salesman. It is by far the worst phone I have ever had. It hangs all the time and now for the second time it cannot charge. I get the message 'stop charging immediately, moisture in the USB port', although there is no moisture whatsoever. Sometimes I get the message if I am not even plugged in. A few months back I took the phone in and the USB port was replaced. Now, not even 3 months on, I have the same problem. 4 people in close relation to me also upgraded to the same model - on my recommendation initially - and they have also had nothing but problems. I have 3 companies that I cannot run efficiently with a phone that is constantly unable to charge or in for repair!! I am so upset and disappointed. Will never buy or recommend a LG product again.