SBG6900-AC wifi router/modem

I bought this modem over a year ago and it never worked right. Whether I am on a wired device or a wireless device my internet will drop for about 5 seconds and then turn back on. I have several devices and it does it to them all. I have had the cable company out several times and they replaced everything and still the problem persist. The internet and the WiFi light never go off. They always look like it's connected. This gets very annoying when I am streaming TV. Seems like the problem started when I purchased this router. Any help would be appreciated. I am ready to buy another router.