Debit order error

a few months back i had changed my debit order to go of on the 25th, though i recently discovered was set for the 26, for convince sake i guess.which i left unchanged. on Sept 25(friday)as usual all the debit orders went through except for vodacom, which i assumed will go off sunday midnight as it normally does if payday is a friday.So i then waited til sunday midnight when it usually went off, to my surprised there was no notification of any kind about the debit on Monday morning the 28th, which then got me worried why it has not went through as there was still enough funds in the acc. i then called vodacom customer service the same morning to find out what might be the problem i & was advised that the debit did strike on saturday the 26th but could not confirm if it went through or not as it was a weekend, i then decided to wait until lunch time see if it will reflect that it went through but still nothing, i then again called vodacom to ask for feedback and was now told that the debit order did go through, for caution i left money in the acc. til 6pm but still no notification. Now on the 03 Oct i get notice call stating i owe the acc. as no funds were available on mon the 28.