unprofessional bank

i had a personal loan with capitec for 61months contract but on my last installment they debited and left an amount of R29 on my credit,on my side i knew that ,that was my last intallment but now that R29 accumulated arrears and they say now i owe them R370.they keep on calling me telling me to pay that amount,they did not even bother telling me that i was owing them R29 for me to settle but they kept quiet so that i will owe them forever.that was unprofessional.and no one is willing to help me in this matter ,i went to capitec branch but all they is the money.my account number is ********** 321