How to delete incorrect VAT adjustment

Hello, @padraig1.

I'm here to make sure you're able to delete the incorrect VAT adjustments in QuickBooks Online without any obstacle. 

Since the return already marked as filed, I'd suggest communicating with our Customer Care Team. They have tools to unfile the return period, so your current VAT will not mess up. That way, you can delete the adjustment. 

You can contact them either of this actions below: 

1. Go to the Help menu, then choose Contact Us.
2. Enter the error in the description box and hit Let's talk. 
3. Pick an option to connect them and submit the request. 

Using direct chat: 

1. Go to this link: https://help.quickbooks.intuit.com/prechats/offerings/QBO-CHAT/22817/view.
2. Complete the required data. 
3. Tap Submit.

Ensure to call them within business hours to guarantee we address your concern. 

After unfilling, you can now delete the adjustment amount by following the steps below. 

Here's how: 

1. Go to the Gear icon, then choose Chart of Accounts. 
2. Find the account you use to add an adjustment. 
3. Tap Run report. 
4. Find the exact adjustment and tap Delete. 
5. Hit Delete again to confirm. 

For more information, check out this article: Create or delete a tax adjustment. 

I've also added articles about tracking the adjustments, creating other tax rates, and other topics. 

• Track tax adjustments
• Create custom tax rate
• VAT Tax

That accomplishes your goal. Let me know in the comment section if you have additional questions. I'm willing to help. Keep safe!