worst experience with closing personal loan account

I had an a personal loan with nedbank and i paid it off on beginning of September 2017. when the account was paid off it had an extra amount of about R198, and that money was paid back to me however whoever paid the refund paid the money twice into my account the second time they paid R298.16 and few days later debited the money back. me knowing that i had settled the nedbank account i reversed the money and called nedbank to find out why are they still debiting money when the account was paid off and that was when they explained that the refund was paid twice. i advised them to debit it back and i was told they no longer have my details on the system so i will have to pay it at the branch. i went to the branch in Nicoleway and they told me they cant pick up my details on their system according to their systems i don't have an outstanding account. i called the personal loan again to find out what is going on they told me on their system the account is open and it has accumulated interest. now here is what makes me angry 1. the money was paid into my account and debited from my account without informing me, i had to call to find out whats going on. 2. even when i have made numeral phones calls even went to the branch to sort the issue its still not sorted and i'm expected to pay the interest accumulated. 3. i have used my resources to sort this matter which was not my mistake. (took a day off lost salary for a day, many phone calls my airtime). 4. i'm very disappointed that i have bee dealing with very unfriendly staff, people who don't understand my frustrations and the effort i've put in to sort this matter. 5. this affects my credit record, since i had this load with nedbank i have never missed a payment but it looks like my relationship with the its ending on a very negative note. i'm very frustrated, I've known nedbank as best bank around SA, but they seem to be proving me wrong with this issue. this problem has dragging for 4 months now and no one is helping me. i would like someone who cares about customers to help me sort this matter, i'm willing to pay whatever was paid to my account but the interest accumulated i don't think they are really my responsibility. your urgent help with this matter will be highly appreciated thank you in advance.