Cable Modem and Email Help Desk

We are private cable operator that has multiple cable modem systems across the US. We currently provide support M-F 8a to 5p for making sure their cable modem is online and for troubleshooting email problems with our webmail system ([login to view URL]). I need a qualified company to be a 24x7 help desk for our subscribers. We would pay per sub per month for support. We are planning on starting with 100 subs and then will start to ramp up from there. Total subs could be in excess of 1,500+ by the end of first year. Please let me know what your prices are for this type of support. We would provide you access to our email server to assist with password retrieval and account issues with email.