Complaint - delayed payment

I am an existing African Bank customer and I app**** for a new loan on Friday the 15th November 2019. This loan was intended to settle my existing account and provide an additional cash advance. The loan was approved and I did a telephonic contract on the morning of Monday 18th November 2019. I then went out of country until Wednesday the 20th November 2019. On the 20th November 2019, I called the sales department to find out why I had not received the payment. The first agent told me that my loan was declined? After pushing her for more information did she finally acknowledge that it was not declined, but rejected due to invalid bank account details? When I advised her that the bank account is the existing account that my current loan is being deducted from and I had sent 3 months’ stamped bank statements as part of the application process, she transferred me to the Sales supervisor. He has been very professional and he tried to escalate the query to the IT department. They have taken a full 48 hours to reply with the same response – bank account rejected? I am currently on business travel and am unable to go into an African Bank branch to validate my bank details. I also find it unnecessary to go into the branch to validate my bank details when it is an existing account that you are currently deducting my loan repayments from and I have submitted 3 months’ bank statements already? It has now been 7 days since my loan was approved and I have still not received the payment.