Missing money

Myself and my 4 friend****anda, Letshego, Ruth, Nokuthula and Evelyn) we opened an investment account last year 2022 with African Bank in Eastgate, we had been transferring an amount of R2000 from each of us to the account every month til December 2022, in the June statement we noticed that there was a R2000 that was not showing, when complain about it we were told to send proof of payment in order for them to do an investigation, the lady who was helping us said the investigation will take 48 hours, indeed we emailed the statements and waited for them to contact us, but they didn't, 3 days late I went to the branch to check how far were they with the investigation, I was told that they didn't receive all the statements I then requested from all of us to drop off our bank statements as proof of transfer towards the investment account, 3 weeks later they are telling us that they need proof not statements, as far as I know the statements are the proofs, that's why I decided to write to hello Peter to assist me/us with regards to the matter