I'll make sure you're able to change your accountant information. This way, you can let your new accountant manage your account to keep your books accurate.
You can remove your old accountant's information by deleting it in the Accounting firms tab under the Manage users window.
Go to the Gear icon.
Select Manage users.
Choose the Accounting firms tab.
Locate the accountant you want to remove.
From the Action column, select Delete.
I've attached a screenshot below that shows the third to fifth steps.
You can also memorize a financial, sales, or an expense report in the Reports menu and send it to your accountant in a recurring schedule. This will let him/her check your account's correctness. For the detailed steps, kindly refer to this article: Memorize reports in QuickBooks Online. It also contains information on how you can export a report to Excel.
Please let me know if you have other concerns. I'm just around to help.