Deleting an invoice linked to an estimate will not reset the estimates' status to Pending. However, it will show as Accepted. You need not worry, you can recreate the invoice and link it to the same estimate. I can guide you on how to do it.
Go to the Sales menu.
Choose the Customers tab.
Double-click on the name of the customer.
Locate the estimate you want to work on.
From the Actions column, click the Create Invoice link.
Making sure you're able to manage your sales transactions is my priority. Have you tried the resolution I've shared? Were you able to successfully recreate and link the new invoice to your accepted estimates?
Know the Community has your back. I’m also here to lend a helping hand. Have a great day ahead.