Delayed transactions due to tech issues

All of a sudden there was a transaction that went through in the 21st of January of R3500 and I was told that there were delayed transaction from December. However, when I checked my account statement, there was never a transaction of that amount that I did on the particular date given which was the 28th of December. Now, I am a small business owner and every penny that I make counts and then suddenly the account gets overdrawn due to FNB's technical issues and for a transaction that I can not see on the stated date.

Please FNB, may you fix my account because I was not helped when I chatted on secure chat regarding this even after calling the ***** hot line, still no help. Please fix this and make my account of good standing again. Thank you