Cash Crusaders – Bought iPhone 11 pro max and it is blocked

I bought iPhone 11 pro max at cash crusades Chris Hani Mall, when I tried to create iCloud, the phone asked for security code and I tried a code for several times, and it blocked me because the code was wrong. I went to the store and the refused to help me. I haven't used the phone but now it is blocked. I bought the phone for R8999 cash, and I am not happy with the attitude I was getting from the store manager. He even left me from the sales floor I went to his office.