Capitec incompetence

I have an account with Capitec. I have taken out a personal loan with Capitec and the arrangement is that the repayments are to be deducted on the 28th of every month which is my payday. I have had an issue prior to this but this month, December 2018, has me wondering whether I should bank with another institution. On the 21st of December I was paid an Xmas bonus from my employer which was promptly deducted from my account as the loan repayment even though it was clearly stated on my statement that it was a bonus payment. I then had to go into a Capitec branch (I have found that trying to sort out anything telephonically with Capitec is useless) to have the transaction reversed. Then on the 26th of December, lo and behold, Capitec again attempts to deduct the loan repayment even though there are insufficient funds (keep in mind that I actually bank with Capitec!) I am so disappointed at the incompetence as have been happy with the service at Capitec (compared to other banks)