Debit order flaw in system

My debit orders were scheduled to run on Monday 2 February 2015. On Monday afternoon I've paid money into my account to make sure that there is enough for all debit orders to go off successfully. After I've made the payment, I went into my account via internet banking to make sure everything is good. Everything was good and no transactions shown on my account other than the deposit I've made. Tuesday morning I've received all the sms's of the debit orders that went off, and I still had a positive balance left in my account. Then on Wednesday morning to my shocking surprise I received sms's one after the other of all the debit orders that returned! This means that there is a flaw in their system, because if the debit orders went off before I made the deposit, then I should have seen the transactions for it on my internet banking, but I did not! Now I'm penalized R120 per debit order, but ii is not my fault! I am VERY disappointed!