Monthly payments should be mailed to: PCDI, Billing Dept., 430 Technology Parkway, Norcross, Georgia, 30092. Unless you have paid your full tuition in advance, you will receive an invoice every thirty days. Your invoice will be for the minimum payment required. However, you may make larger payments at any time.Remember: your tuition is INTEREST-FREE. Please be prompt in mailing your payments, whether or not you have received your next shipment or have completed your lessons.