Is this how you treat customers after them doing business with you for almost 20 years?

I sent an email on 04 December 2020 to complain about the poor service I received from SBSA ***** department on 03 December 2020 and to date haven't had any response.

I received a call from the anti***** department which was highly appreciated on 03 December 2020 at 12:48pm regarding suspicious transactions on my account. I tried numerous times to explain what was going on and the agent whom I was talking to eventually turned around and told me to keep quiet because he is still speaking. How do you talk to a customer that way? I feel this is highly unprofessional and rude! How does a staff member treat a customer like this? He was also extremely impatient with me when I asked what the next step to be taken would be with regards to activity on my account as this was the first time that I have ever had an experience with suspected ***** on any of my accounts and was not sure what the process is. This is the first time in my whole time being a standard bank client that I was treated with such disrespect. I have had an account with standard bank since 2002 and have always been treated fairly and with respect. This is highly disgusting and I hope that this staff member's attitude will be addressed.