So this is interesting to me because lately, I've been looking for a VPN that would work for my little brother who is trying to make it to the point that he can stream full time on Twitch. The problem is that he has been targeted by script kiddies, who found his IP address through Skype. Shame on you skype. That said, I've been looking for a good VPN for him. It seems that ProXpn isn't as solid as I thought it was be…
A famous StarCraft streamer made a guide on how to avoid this:
https://blog.destiny.gg/protection-from-ddos-attacks/
I googled "guide to preventing DDOS on twitch" and it came up as the fourth result. How hard did you look?