I was experiencing the same thing when I am in Mainland China, but I am outside the GFW most of my time. So if there is any mma installer you want, i.e. the mac or linux version of mma 10.1 or some future release, just PM me in zhihu, I would help if I can.
PS: I think a paid VPN is stable enough to download the installer, last time when 10.0.2 was released, I downloaded the installer via VPN.