Poor service

I have an account with Realpeople and on the 9th of May I deposited R5000. 00 at the standard bank ATM trying to reduce the balance I had, however I did not include the correct reference and used my initials and surname as a reference instead of using the reference number that I was supposed to have used. The receipt I got from the ATM was lost, I tried contacting them so that they can rectify the mistake even went to the bank to seek for the duplicate and the bank emailed them a letter that proves that I have made the deposit and now they can't help me because they are saying it's not a prove enough, please help me.