Hathway Broadband Internet Chennai - Hathway modem LOS light was showing every 15 minutes now Not Turning ON

I am residing in Velachery chennai. From past two weeks in my modem LOS (Loss of Signal) light is showing every ** minutes. I have to turn off and on the modem every ** minutes. I have literally raised around * tickets. The most irritable thing is they(customer care) are calling nd telling we ll resolve your issue soon. Later ** minutes the ticket which I raised is automatically closed. As this is pandemic period I am dependable on this modem for work from home. I am getting severe warning from my office due to this issue. I recently spend **** to buy jio m* wireless router for my official work. But they never miss to call you during payment due time... I am completely frustrated. I lost my self respect in office just because of their poor customer service. Please help me.