Manual transfer of money

I inherited money from my mother's estate and when I went to the Nedbank Cresta branch to make a payment for a house, I was sent to inquiries and the teller told me that the funds were too large as my account had a sudden jump in funds and they need to investigate where the money came from as it could be **********. I took the proof where the funds came from but he said that my proof could also be ********** - I was made to feel like a ******** and after being in the bank for 2 hours waiting for a consultant as I was not happy with how I had been treated at inquiries I was told I had to go back to the same teller and had to fill out a manual transfer of monies - which I did which was uncomfortable to say the least. After 2 days the money had not been transferred yet ........ so I went back to the branch and was sent to inquiries again and I was told it would take 6 days to verify where the funds came from into my account. WHY........ If the funds have already been cleared and are available in my account, should I have to wait 6 days to verify where the funds have come from and to make a transfer on my account?