Modem keeps restarting

So I have had some connection problems for about a month or two. Sometimes the modem will turn off or give a red light and it will need restared. The past 5 days or so it's been restarting itself just about every hour. We can't do anything if our internet keeps going out. I tried calling but everytime I do the service goes out again. Is this something I can fix or will I need to replace the modem? I'm just super upset by this I pay way too much for this to keep occurring.