No after sales support

Purchased a Sunsynck inverter thinking I'm getting the best, inverter is awesome but the after sales support is terrible. The wifi data ****le stopped working, I was asked to send the ****le in which I did the ****le was tested and is working. They now want me to remove the entire inverter as they do not send technicians out to you. The issue with the ****le is minor seems as thou the input connection is faulty, this is a little PCB that can be replace onsite, its connected to the main PCB with a ribbon cable.