The Knowledge Academy - Purchased a course but they are not allowing to give exams

I had purchased the course "Prince* Agile Foundation & Practitioner" from The Knowledge Academy. Their representative told me I can give the exam later also within the course span of * year. Now when I am trying to book the exam, they are declining my request and asking to pay more money to extend the course. They are saying as per the organization terms, I should have completed the course within ** days, but this was never mentioned to me in e-mail or verbal communication. How come I would know such loop holes to harass consumers and loot them further. Right now, I am not able to book the course and I feel I would not get my money back also.