I have filed my VAT return, after i filed it i downloaded the calculations and realised it had incorporated the entire year from 01/07/2019 - 30/03/2020 instead of just the quarter. So it has included everything, so looks like i owe HMRC alot more money then i do. How do i fix this? I have downloaded the CSV files and calculated what it should be.
If you’ve submitted it to HMRC already then you will have to talk to them to see if it can be amended.
On the QuickFile side you would temporarily disable your online VAT filing settings, then roll back the return in QuickFile and re-save it with the corrected values, but that won’t change what you’ve submitted to HMRC, the only way to fix that is to ask them directly.