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keijzers(Newbie)Newbie
12 Mar 2026

Hi all,


I have been trying to lodge my BAS for 2 weeks now. I have been getting the same errors even though all my information entered is correct. I needed to make a variation on the installment amount that the ATO automatically calculated for me. I filled in each field as i always do, with the correct info but still the same errors. The errors are:

  • Variation is not allowed and amount at 5B is greater than zero
  • You are unable to vary online, contact us (i did, they cant even lodge)
  • The net amount does not match our calculated net amount

It is at the point where my BAS is now overdue so i called the ATO to see if they could lodge the BAS for me but even they could not figure out why. Then the phone hung up on me. I had to wait over an hour to even get a hold of them then i was hung up on. There is no email to contact either so i am trying to get in touch here. I don't have time to wait hours on the phone with no solutions. I am also not paying a tax agent to look into this as it should be a simple lodgement like all my previous quarterly lodgements i have done on my own. What do i do? Do i seriously have to write a letter and send to them? its 2026...not 1950

85 views
5 replies
85 views
5 replies

Most helpful response

Most helpful reply

KaraATO(Community Support)Community Support
13 Mar 2026

Hi @keijzers,


Just off the back of what @YellowPotato has said, are you trying to change your PAYG instalment amount/rate, or fix a BAS figure (like GST or PAYG withholding)?


For PAYG instalments, when you see errors saying, 'variation is not allowed' or 'you are unable to vary online', it likely means you'd need to contact us so we can look at your account and work out what's blocking the variation.


The error about 'net amount does not match' could also be a technical problem. You can try:

  • clearing your browser's cache and cookies,
  • logging in again using a different web browser like Chrome or Firefox.

If it’s your BAS, you don’t 'vary' a BAS. You either correct the mistake in your next BAS or lodge a revision of the original BAS online.


If you're still unsure, I'd recommend the following:

  • reach out to a registered tax/BAS agent to help get this sorted for you, or
  • phone us again (individual for PAYG Instalment and business for BAS) - if it's a system issue and they can't resolve it over the phone you can ask for the matter to be further investigated.

I just wanted to also mention, the system may automatically apply penalties and interest for late lodgment and payment. If this happens, you can look at requesting a remission. 

All replies

YellowPotato(Taxicorn)Taxicorn
13 Mar 2026

I'm assuming this is a quarterly BAS and for Dec-2025. So you are trying to claim back the PAYG instalment you paid in Sep-2025?

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Liked by cwatkins

Most helpful reply

KaraATO(Community Support)Community Support
13 Mar 2026

Hi @keijzers,


Just off the back of what @YellowPotato has said, are you trying to change your PAYG instalment amount/rate, or fix a BAS figure (like GST or PAYG withholding)?


For PAYG instalments, when you see errors saying, 'variation is not allowed' or 'you are unable to vary online', it likely means you'd need to contact us so we can look at your account and work out what's blocking the variation.


The error about 'net amount does not match' could also be a technical problem. You can try:

  • clearing your browser's cache and cookies,
  • logging in again using a different web browser like Chrome or Firefox.

If it’s your BAS, you don’t 'vary' a BAS. You either correct the mistake in your next BAS or lodge a revision of the original BAS online.


If you're still unsure, I'd recommend the following:

  • reach out to a registered tax/BAS agent to help get this sorted for you, or
  • phone us again (individual for PAYG Instalment and business for BAS) - if it's a system issue and they can't resolve it over the phone you can ask for the matter to be further investigated.

I just wanted to also mention, the system may automatically apply penalties and interest for late lodgment and payment. If this happens, you can look at requesting a remission. 

keijzers(Newbie)Newbie
16 Mar 2026

Hi @KaraATO,


Thanks for the response.


To clarify, I'm not trying to claim back the PAYG instalment I paid in Sep-2025. I'm trying to vary the PAYG instalment amount for the Dec-2025 BAS, as the instalment calculated by the ATO ($1,096) is significantly higher than what my actual business income supports.


I run a small side business and my sales and profit this year are much lower than what the PAYG instalment seems to assume. I attempted to vary the instalment using the T8/T4/T9 fields with a revised annual estimate, but the system shows the errors “variation is not allowed” and “you are unable to vary online, contact us.”


The BAS summary then also shows the “net amount does not match our calculated net amount” error, even though the GST figures appear to calculate correctly.


As mentioned, I have already called the ATO and they could not lodge either and had the same errors as me. I dont have time to wait hours on the phone.


Thanks



cwatkins(Enthusiast)Enthusiast
13 Mar 2026

The March BAS has most likely generated therefore you cannot correct the Dec BAS PAYGI figures and in the March BAS you may can claim a 5b credit. Cant claim a 5b credit in Q1 wont let you. Maybe this helps. I would call ATO.

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