Guild Wars 2

Hello! I am from Hong Kong.
I don’t have this high ping problem before. (usually 200-300 ping)
But I had this problem during night time since 2 weeks ago.
I will not have this problem when my time is 8am – 6pm.
After it, i will have unstable ping like 500+ and 1000-4000 ping in WvW.
I called my ISP and they checked my network and changed new equipment for me.
The problem still happenes.
Hope anyone can give me some idea & solve this problem.
Thank you!

I am looking for Asia/ Australia time zone guild.