Poor service and inverter repairs ***********

I had booked in my inverter for repairs, in early April this year. It was allegedly repaired after a week but when I took it home, the cooling fans were not switching ON and it kept tripping on overheating. I took it back within 2 days of receiving it, for that fault to be corrected. I am yet to receive my inverter back fully repaired and functioning, it has been more than 8 weeks now since they have been "working" on my inverter. The sad part is I have paid for the repairs in full and they seem not to be prioritizing my inverter or they dont know how to do proper repairs. They do not communicate with me to provide timely updates unless if I call them, of which they will tell me lies and empty promises that the inverter will be ready by the end of each week that passed by. I want my refund so I can try another service provider, who takes their customers serious.