My network provider give me speed 100. 

In my room i cant make cables so i go to powerline. First i get AV500, and it gives me speed 50mbps but it suddenly disconnect for a minute or two and back. So i lose nerve and get AV1300. First, it gives me speed 65-75, i was very happy. I have this a couple of days i still not sure do this device disconnect. But, later that day speed go down to 30, and dont want to go high anymore.

Advices? I dont change anything, powerline alone go to 30 and dont want to back to first speeds he have?