Bank Reconciliation Out since since setting up bank feed

Hi,

Since we set up our bank feed, our reconciliations have been out. We have narrowed it down to a specific day in January.

The reconciled balance is correct on the 20th, and when we select the 21st, the balance jumps up a specfic amount (which we have narrowed down to a specific set of transactions on the 21st), without those transactions being reconciled. We cannot see anywhere that these transactions have been entered twice.

We have spent hours on this firstly isolating the date it occurred, and then spent 40 mins on hold with MYOB only to get the call disconnected before actually getting to speak with someone. 

Can anyone help?