Modem blinking green and orange

My modem stopped working four days ago. After trouble-shooting and following all the steps online, I scheduled an appointment for two days ago. The tech installed a new modem, which worked for a few hours, and then did not work again. So I went online for more trouble-shooting on the new modem (several times). After following all the steps, I scheduled a second appointment for yesterday. The tech installed a new modem, which worked for 8 hours, and then did not work again. So I went online for more trouble-shooting on the new modem (several times). After following all the steps, I just scheduled a third appointment for tomorrow. It feels as if this is an infinite loop. And it's costly. I work from home and am having to juggle these tech appointments while burning through my cellular plan using a personal hotspot in lieu of Xfinity service. Does a solution exist?