No communication and they disrespect their customers

I have app**** for a loan application at african bank on the 27th March, I was requested to send through the required documents which I did. I followed up after 2 days and I was was told to send through March bank statement and I sent through. No communication was made from their side and they took time to inform me about the second offer, I had to call them almost everyday for the status on the application, on the 9th I received a call with the second offer, I signed the contract and I was told the money will be in my account within 12 to 48hrs and we did the Debi check mandate which I've accepted. Last night I received messages from my bank stating that the Debi check has been canceled. I then contacted african Bank this morning, I was then told that the application has been EXPIRED I mean really???? We have finalized everything on Friday and I was told the money was be in my account the very same day or latest Monday.... Who's fault is it that the application has been on the queue for two weeks??? You guys you don't communicate, and why does the offer expire whereas u've finalized application. I'm frustrated with African Bank