the MCI Inmate Services number is 800-231-0193.
MCI High Toll Department is 800-937-1048.
Verizon Inmate Calling is 800-686-2611.
VSSI (Verizon Select Services) is 800-433-4518.
ILD Teleservices, Inc. is the company that handles the billing on behalf of VSSI.
To set-up an account with VSSI (if you have AT&T as your local provider or one of the other ones who don't do third party billing), their number is 800-453-1437.
To find out if you have a block on your number
MCI 1 866 770 4896