Problem with upgrading phone through Upgrade Program. Says I owe more and more each month on the eligibility page.

Does anyone know how to find your Citizens One Bank loan number for iphone upgrade program? Receipt is gone and I can’t reach them by phone to ask them why my loan for my iPhone hasn’t been paid off (as I’ve had it for almost 22 months now) and the amount I “owe” to upgrade keeps increasing by about $100 each month! I’ve spoken to Apple and they tell me to contact the Citizens One bank directly and when I call them it goes to an automated voice saying I need to contact Apple about anything regarding the upgrade program. I’ve resorted to making an online account with citizens one regarding my upgrade but can’t find the loan number.