Do the original employment/training contract period and extended employment contract periods count as one?

I joined an organization as an accounting apprentice under one year training contract. As per the terms of contract, the co. agreed to pay my educational expenses during the training period. The terms of the contract explicitly state that If i discontinue my training before one year, I am bound to refund all the amount the co. has spent on my education. At the end of 1 year, my contract was extended for another year with clause 'all the terms of contract remaining unchanged'. At the end of second year, the training contract was extended in the same way for the third consequetive year without any break between the contracts. The co. paid my fees during all three years as I continued to pass my exams. shortly before the end of third contract I found another training program somewhere else. After serving one month notice period, I left the organization. Now i am informed that I have to pay all the educational fee the co. paid since inception, i.e from the start of first training period in order to get my relieving certificate and experience certificate. However i feel that as each contract was for one year only, I am bound to refund only the fees that has been paid during the current contract period as I did not breach any of the first two contracts and duly completed without any break or breach. The HR says if I dont refund the amount, there'll be a case of recovery against me for the amount. I need a legal opinion as per the general employment contract law, whether the extentions of training contract for two years bind me to refund all the fees paid during period of all three contracts; one initial contract and two extentions. or I have to refund only the fees that was paid during the current contract period by the co. ?