Unexplainable debit order and variances on my account

I generally have had no problems with FNB and they are generally a good bank. However there is a variance on my account and none of the 3 agents I have spoken to can assist me or even explain the R819.00 debit order that is reflecting on my statement, nor the variance of R198 on my account. According to them all is alright with my account, no variance and at first the debit order of R819.00 cannot be traced and the no such debit order exists. I spent an hour on this, talking to FNB and no one can help me. Can a manager or someone higher up in FNB explain to what your consultants cannot... I have screenshots of all the conversations.