Individual — HP Monitor Model 24f

I have purchased HP 24f Monitor on line from Amazon on 22/07/2021. The monitor is working fine but yesterday i noticed a thin green line running from top to bottom on the left side of the screen and wanted to eliminate it. I tried all possible methods to eliminate but in vain. I contacted your recommended service numbers getting it from net. some numbers were disconnected and some not answered. I am 86 years of age and living alone not able to get a right service personal of your dealers and helpless. Please try to help me in this regard for which i am very much obliged to you.
Regards c v padmanabhan