To be honest the only solution is to wait. Attackers paid for certain amount of "ddosing time". We have to wait until they run out of money. Otherwise we have to buy ddos protection which would cost us much more that attackers paid. It is sad but it is true.
PS
ISP doesn't help a lot. They are periodically disconnecting our server from internet because they are "protecting" their network.
I'm completely ignorant on how much this kind of stuff costs. How much would you "wild ballpark guess" that a DDOS like this would cost, and how much would the DDOS protection cost? And who would you pay the DDOS protection cost to? Your server hosting company?
https://encrypted.google.com/search?as_q=DDOS%20protection%20cost&lr=lang_en-CA&ie=UTF-8&oe=UTF-8
Always one smartass out there. Let me help your ignore button become a little more yellow.
And I will return the favour you lazy shit.