• Are you trying to amend an IAS/BAS? please check this guide on how Importing activity statement lodged indirectly 
  • Can you please try to manually delete existing AS and pull the new one.
  • Note, you cannot vary instalments past the due date on the BAS. You can only do that via ATO portal. Please contact ATO in such case. In case ATO is not able to help, please adjust it at year end.