Bad Service and no consideration for clients

I have a personal loan with nedbank that I have been paying monthly for 2 years, all my accounts are with the bank, car , bank account, credit card etc. The month of January was the first time I was unable to not make a payment and when contacting the bank for a payment I was advised via their online options I will get a call back, this was never done and 2 installments were debited form my bank account. I submitted a complaint and done more phone calls and was advised a partial refund will be done, nothing happened and when I called back i was told my request was declined as I made no payment arrangement. The bank treats clients very poorly who are struggling and who has been loyal with their payments arrangements