Your accountant missed a BAS lodgement: what to check next

Confirm what has actually been lodged
You sent the figures to your accountant and expected the business activity statement to be lodged. Now an ATO reminder has arrived, or your online account shows an outstanding period. Before deciding what went wrong, establish the current position from the records.
Ask which statement is outstanding, when it was due and whether the ATO has received it. A prepared form, an email asking you to approve it and a completed lodgement are different stages. Keep the acknowledgement or receipt that confirms the final stage.
Write down any disagreement between the accountant's records and the ATO account. This gives you a specific issue to resolve, rather than relying on a general assurance that everything is up to date.
Source: ATO: How to lodge your BAS
Keep lodgement and payment separate
Check two things for each period: whether the statement was lodged and whether the amount due was paid. A payment record does not by itself establish that the required statement was lodged. Likewise, a lodgement receipt does not establish that the account balance has been paid.
Ask your registered tax or BAS agent to reconcile the statement, payments and current ATO account. Include amendments, credits and any existing payment arrangement in that discussion, so the same amount is not mistaken for a new debt.
If money is short, raise the payment problem promptly. Do not assume that delaying the statement will resolve it. Ask the agent what must be lodged and what payment options can be discussed with the ATO.
Source: ATO: Setting up a payment plan
Put the documents in date order
Gather the engagement letter, records you supplied, requests for missing information, approvals, lodgement receipts and ATO correspondence. Include any notice received personally as well as letters addressed to the company.
Make a simple timeline showing when information was requested, supplied and approved, and when lodgement was confirmed. Keep the original messages and documents behind it. The timeline is a practical aid for your adviser; it does not decide who is legally responsible.
If the accountant says a different due date applied, ask for the basis and supporting record. Have your adviser check the relevant date rather than calculating a legal deadline from an assumption.
Have personal notices assessed promptly
Using an accountant does not, by itself, remove a director's responsibilities. Some unpaid company tax liabilities can also expose directors to personal penalties. Whether that applies depends on the liability and the relevant circumstances.
If you receive a director penalty notice, give the full notice and envelope to an appropriately qualified adviser promptly. Ask them to check the dates, reporting history, amounts and available responses. Do not treat a discussion about who missed the lodgement as a substitute for responding to the notice.
This record-checking process does not determine whether a penalty is valid, whether a defence is available or whether a particular company procedure would affect liability. Those questions require assessment of the actual documents and applicable rules.
Source: ATO: Director penalties
Agree who will do each next step
Ask for a written list of missing information, outstanding statements and actions required from you and the accountant. Give each action an owner and a follow-up date. Request confirmation when lodgement is completed, rather than assuming a promised date means it happened.
For future periods, agree how you will receive reminders, approve statements and obtain lodgement confirmations. If the accountant changes, include outstanding periods and unresolved correspondence in the handover.
Bring the reconciled account and timeline to your adviser if the business also cannot meet its debts. They provide a clearer starting point for discussing the company's position and the next steps appropriate to its circumstances.