If you don't lodge your BAS on time, the ATO could charge you a late payment penalty. For small businesses one penalty unit is $222 (as of 1 July 2020) which is added every 28 days after the statement due date. If you've been charged a failure to lodge (FTL) penalty and you lodged your BAS through a registered BAS agent, you usually don't need to pay it if you can prove that you gave the agent all of the required info to lodge your BAS on time.

The last thing you want to do is avoid contacting the ATO. If you can't lodge on time or need a payment extension just give them a call as you may be eligible for an exemption or payment plan.