Hi 

P9 Deco Ac1200 + Homeplug AV1000

my main P9 has not been touched or moved in the past 6 months, it has 2 Ethernet cables going into it and the power cable. I've tried using different cables and power lines yet I still get a loud buzzing noise, one that you could not sleep with, that's for sure. Luckily I sleep in another room but we're having guests round and wouldn't like to subject them to this in future. 
please can you let me know how this can be fixed or replaced, it's quite unbareable. I got this from Amazon during December of 2019. 
 

thanks for your help in due course,

tony