VPS Server - Plesk C/P Debian O/S

We have 10 domains on a Plesk 8.X VPS server. Our concern is incoming and outgoing email. We send 100K emails through the server daily, we need someone to help maintain the server and the Qmail application. We need the assiatance of someone proficient Plesk and with this environment. Looking for someone with experience in this type of environment. Need assurance that provider can be trusted to be given access to our server. We need someone who can dedicate 1-3 hours per week supporting our server and mail functions.