******* and ********* business practices

On the 24th of September I transferred R500 from FNB into my Discovery Account as I didn't have my FNB card on me, and not enough money on the Discovery card. I only had R300 left, and the I needed R350. After the transaction I then paid that R350 and the balance was R463.10. Yesterday I get an sms of R500 coming off my account, called Discovery as it was a suspicious transaction. I am being told that there had transferred R500 twice in my account, which is not true. I never used that R500 they are referring too and it never reflected Inyo my account balance, after I transferred R500 there was only R800 in this account and after I used R350 only R463.10 was my balance, now if Discovery has some faulty systems so they can ***** money from its clients, I am certainly not one of them. I want my R500 put back into my account because you have now ****** R500 from my current balance. I will be tweeting this. I am so sick of Discovery. I want my money back and thereafter I can close this account.