Constant modem restarts

For the past 3 weeks straight I have been dealing with constant disconnects because of my modem restarting on it own. I have had 3 different technicians come out to my apartment and none of them have been able to resolve the issue. The have replaced my modem on the first visit, I used to have the xb7 they upgraded me to the xb8. The issue still persisted. On the second visit the guy that came out removed the splitter for the cable boxes since we weren’t using them so the line coming from the source outside was going straight into our modem line. This did not resolve the issue. The last technician that came out over a week ago said that the 2nd technician made the issue worse by removing the splitter so he replaced it with a new one. While he was here he also replaced all of the lines in the apartment itself including taking the wall plate off where we have the coax cable plugged in and replacing all of that. I was told by the last technician that since the modem is restarting it’s not a true outage and is an intermittent issue so they would not send anyone from the network team out to look into until Monday. He gave me his number to text him and advised him and his “boss” were going to monitor our connection over the weekend and put in a request to send someone out last Monday. I called and texted him Monday to get an update and have been completely ignored. I am tired of requesting a technician come out to look at this when all it feels like they do is lie so they can leave.