Decline Homeloan due to unpaid debit orders

FNB Declined our Homeloan due to debit orders that must go off the 28th of each month, but FNB takes it off the 27th, now it looks like the debit orders failed, but my debit orders dates are the 28th and the 28th when my salary gets paid the funds go off, I'm very unhappy with this as this has happened how many times now when the 28th falls on a Saturday FNB goes and let the things strike the 27th or even the 26th, that is not my agreement that was signed with the credit providers and now we can't get the home loan due to FNB that takes money off whenever they feel like it, i will have to move my accounts now to another bank as this is not my (the consumers) fault, but rather FNB.