Read the full knowledgebase article and know where do your clients manage their VPS.

Clients manage their VPS at http://portal.controlmyvps.com.au/ 

This is a generic domains, the whois leads to a parent company which is not traceable to VPSBlocks. This is because we realise our resellers want us to be pro-active about isolating ourselves from their clients. We have absolutely no contact with your clients, as far as they are concerned you are providing the service directly to them.