200% of a 2 core VPS

I've got a client hosting a WordPress website with a hosting company that's running the account on a 2 core VPN with 200% speed assigned to the account. A reverse DNS lookup shows that the same IP address is hosting another 20 accounts. I can only assume that they have all been allocated 200% The server has crashed at least 3 times in the past two weeks that I'm aware of, but the hosting company is blaming our clients Wordpress site. They're running WHM and Cloudlinux on the VPS. I'm pretty sure that 200% of two cores is not a good idea, but I would like to hear some feedback from some experts. I'm also pretty sure that the 2 core VPS has 8gb of RAM.