On every thermocopy/centriworks printer, there should be a little metal tag with 2 phone numbers - one for SUPPLIES and one for SERVICE.
Supplies: 865-524-1124
Service: 865-524-1301
There is also a 5 digit equipment ID stamped on the metal tag.
To get more toner, call the SUPPLIES phone number (865-524-1124). They will ask for the 5 digit equipment ID and what supplies you need. Tell them what color of toner you need, and they will ship it to the school. They may ask for a contact person to ship it to - you can have it sent to your school's tech TA or to yourself if you're going to be the one changing it.