The balance on the account on QuickFile is derived from the transactions. If the balance isn’t correct, it sounds like there may be some missing transactions - as you suggest.
We’re only able to pull transactions in from the last 21 days (which can be done from the “More Options” menu on the bank statement view). Anything previous to this would need to either manually input or imported from an export, such as a CSV.
If you are able to get a CSV from your online banking account, this is likely to be the quickest and easiest way to bring the account up-to-date.
Please let us know if you require any help with this.