I was hired as a CEO at an <unnamed> company ($200m+ revenue) and we were hit by this type of attack.
Every second of being down cost us literally $10k, so we quickly negotiated with criminals for $5k one time payment and they stopped the attack.
Unfortunataly a few weeks later we were hit by 3 new attacks. Apparently the word had spread and these new attackers demanding $50k.
We were not going to pay $50k but I was also unable to stop the attacks. I was let go a few days later as we had a down time of 2 days and I wasn't able to fix this problem.
Source: 3rd world south america