I'm going to start off by explaining. My internet goes on and off randomly. There's absolutely no explanation to it. Everything via LAN works perfectly, but the internet is having real issues.
I'll start off by explaining how my setup is. I live in an apartment. I don't personally pay for my internet, the owner of the apartment does. I'm pretty sure that he pays for the whole building, not per apartment. I have 2 routers. One that came with the place and a wireless router that I own. The internet comes into the main router from an ethernet cable in the wall that plugs into the WAN port (of the main router). This main router, acting as a DHCP Server, has a single computer connected to it's LAN port. Also in the LAN port an ethernet cable connects to the wireless router. That cable connects (from the main router) into the WAN port of the wireless router. The wireless router acts as a DHCP Server as well, but only on the 'wireless LAN' network that it creates. I connect a laptop and my phone to the wireless router via WiFi.
Here's a picture to help explain.

Everything was working a little over a month ago (and I didn't change any hardware at all) and it just randomly started having issues. Here's a screenshot of me Pinging google from my PC.

As you can see, without me touching anything, it just randomly works, and then doesn't. And then it works again, and goes down. Sooo weird. I had this issue with all of my devices (Computer, laptop, phone), so I assumed that it wasn't my devices fault, that it must be the router.
So I took out the main router, and put wireless router in it's place. Like this:

It had an issue with my ISP asking for login information after I did that.

I said that I didn't pay for my internet, my landlord does, so I don't have this information. But I fixed that by spoofing the MAC address of the MAIN router to the WIRELESS router and it worked.

I was able to get onto the internet using only my wireless router. (taking an extra node out of the picture) The problem IS that it STILL is having issues.
It's not my devices. They all work fine if I ping each other within the LAN. And it's not the router because I switched it out... What could be the problem here? I'm not normally stumped, but this has got me. Ideas?
