There are some ways to defend against DDOS attacks, they're all pretty flimsy band aid like fixes or very costly and still not 100% effective lol. When the attack is large enough at least, you can absolutely defend against smaller attacks and even out buy their attack power - lol sounds like a game, someone should make DDoS the game XD.

Unless there is some serious vendetta by these attackers it would just make sense to have some minor aids (that won't be super effective) and wait it out.