I have several 'accounts receivable' such as cleaning, customs, fuel, pest control etc but afaik they shouldn't be accounts receivable, they should be 'expenses'?

You can reclassify or move transactions in QuickBooks Online to correct any misclassifications.

Moving transactions from one account to another is possible. However, it depends on how you recorded these transactions. If you've added these transactions manually and have categorized them as Accounts Receivable, we can manually undo these categorized transactions and then record them as an Expense.

Here's how to manually undo the categorization:

1. Navigate to Bank Transactions.
2. Click Categorized.
3. Choose a specific transaction, then click Undo.

Once done, go back to the For Review tab:

1. Choose the specific Bank Transactions.
2. On the Category, select Expense.
3. Click Confirm.

On the other hand, if you're using QuickBooks Online Advanced or have an Accountant, you can use the Reclassify feature to move multiple transactions from one account to another.

Also, if you have any doubts, I suggest consulting a professional accountant or bookkeeper to ensure accurate financial records. 

Moreover, if you need to reconcile an account, please refer to this article for guidance: Reconcile an account in QuickBooks Online.

Let me know if you need further assistance moving your transactions from one account to another or QuickBooks. Keep safe.