DNSimple experiencing another major DDoS attack

Is there anything we can do to mitigate downtime at the level of our DNS provider? It seems unlikely to me, but this is the right group of people to ask.

They've already had two major attacks. One was in June of 2013 (http://blog.dnsimple.com/2013/06/incident-report-20130603/) and another one in September of 2014 (http://blog.dnsimple.com/2014/09/incident-report-ddos/). I'd probably pull the plug on their service, or have some mitigation plan in place if you stay with them