Internet crashes

I am randomly getting these internet crashes and its extremely frustrating.

So just now, while on my Playstation, which is WIRED, my internet crashed. My game was extremely laggy, the speed test specifically on the Playstation had me getting less than 10 mbps. Mind you, this has been happening for a couple weeks. This time, I was prepared. I quickly ran to my wireless laptop, did a speed test, 3 mbps. Then I ran all the way down stairs to my wired desktop, 10 mbps. 

I contacted Cox, and the representative basically said "its you, not us" 1000 different ways. The modem is relatively new, my services are relatively new.

Anyone can help? Resetting it has helped it maybe for a few hours, before it just crashes again. This is ridiculous.