Vat return rejected as wrong dates. need to open vat return and change dates but it wont allow me to do so

Hi there, phil33.

Since you're unable to open a vat return and you won't allow you to change the dates, I suggest raising unfile requests for Vat dates. To do that, you'll need to contact HMRC to help you with the process. 

Once the unfile is done, you can now change the correct dates. Then, file and resubmit again to HMRC. To do that, choose to Resubmit return against the period. This will open up your return. Select Resubmit to HMRC to go through the process again.

For additional information, you can check this article: Submit a VAT return in QuickBooks Online. This also provides what are the reasons caused HMRC to reject your VAT return.

I also have a few references here that we can look into on how to report your VAT returns:

• Submit a VAT return in QuickBooks Online
• Submit a VAT return to HMRC - MTD for small businesses
• Record a VAT payment or refund

Please know that you're always welcome to swing by anytime if you have other questions or concerns about QuickBooks. We're always here for you.