Ridiculous loan repayment

on the 18/03/2015 I was approved for loan of R60,031.47 then capitec settled existing loan of R10,607.48 then i got cash of R49,423.99

over 55 months with an installment of R2,145.71 after 3 or 4 months of paying I increased installment to R2250, in November 2016 i reduced it to 1599.00 due to employment changes from my previous employer, November 2017 i went to one of your branches as I wanted to increase my installment, only to be told that I am not allowed to increase the installment and there was no given reason and i was told that when i reduced my installment it automatically expand the months to 70 months and i don't remember anyone telling me that, when i check my statement i see there is an interest of R1200 or so and i don't get that too, When i calculate my loan repayment will be R156512.80, from a loan of 60.000 I don't find this fair at all, regardless of how it has been calculated, this is ridiculous