Loan debited twice, poor customer service.

In December I was debited R4040 twice, this was a bouble debit. I tried to reverse butt and nothing, I spoke to a consultant but they were useless. I sent an email 3 times but nothing. Uses thd app, but still nothing. This has been more than a week now. Now I'm using overdraft of which I'm going to be charged fees. This was the bank mistake and now I'm suffering. Poor service, I'm being inconvenienced. I'm looking to chenge banks and just pay them what I owe them because this is unacceptable.