The worst experience ever

I had taken a student loan , I think this was in the year 2014 if i'm not mistaken made my Mother the surety , We had been paying it every month from the date we took it , the interests increased crazy the amount we where paying every month didn't make any difference fast forward to 2017 I decided to pay off the student loan , asked for the settlement amount the amount that I paid was greater than the settlement amount given to me , because I was transferring from FNB to Standard bank account nevertheless I didn't expect any refund , asked my Mother to call in and ask for the cancellation and settlement letter they tell her to go to any standard bank branch and get the letter from there and I also have a refund to collect, she gets there and they ask for me personally . I get to the Standard Bank Southgate Branch on the 31st of December they tell me I've got a refund of R 700 and some odd rands okay , I get to tellers they give me the amount okay fine at that moment i thought my account with them is cancelled because they assured me but no ,so they still went and debited my Mother in December and January after I had settled the Student Loan. Yesterday on the 28th of January I get a letter from Standard bank stating that I owe them an amount of R 500 and another on says R 57 , I call the customer services department they can't give me any answers instead they telling me to go to JHB town and close it there , why should I be taken from pillar to post to close the damn account. I don't recommend the Standard bank Student loan to anyone they even ******* newly graduates that are still finding they feet disgusting.