They don't care about customers, especially customers with no money

I was ****med money from fnb, I reported the case, but fnb want a prove of Sim swap, I did provided the prove, two proves, but they saying they want a letter from MTN ***** desk report, which I am failing to get, mtn is not willing to help, I don't know wher to go for the letter, I called mtn day and night, but no help, I evn call the ***** department but no help, I went to the branch no help, can they pls tel me specific wher I can find the letter, m so tired of fnb, m 109%surr when I am done with ds case. I am done with fnb, for life, m leaving fnb with my whole family and friend, they've seen me crying like a baby over this case for soo long, from 7th January, and when you ask questions like how can someone locate my savings on 32 days notice acc and take the money and close the acc using a Sim card, I got no answers, I want them to tel me what to do now because I am failing to get what their asking