Standard Bank ATM deposits faulty

Standard Bank in the Eastern Cape has reduced their branches with tellers on to two and as a business owner who regularly has to pay accounts with suppliers who bank with Standard Bank. I now have to use an ATM to do these deposits which is firstly not safe and secondly as I found out not reliable. After depositing a large amount the ATM malfunctioned and the cash was accepted but the transaction not processed. After losing my cool and 2 hours later, the branch manager at The Walmer Park shopping centre store provided a letter of confirmation of my deposit to give to my supplier as proof of payment stating " due to a technical error we will manually process the deposit" which I took to imply the deposit (cash-immediately reflects on the recipients bank account) would be processed that day 2nd July. Today supplier advised as at 4th July the deposit was not reflecting. After 3 hours of phone calls eventually I get hold of bank manager who advises she is still waiting for the deposit to be done and it may not happen today either. Now who is responsible for interest payments now due to my supplier as theoretically my account is in arrears with them even though the cash deposit was done on the 2nd July when it was due. The service at Standard Bank is actually worth a minus star however had no choice but to select one star to type this review. Any corporate looking to change banks do not EVER consider Standard Bank and rather look elsewhere