How can I deal with the situation where some customers are also suppliers? Do I have to register them as a supplier with a different name?

You can add a unique character to your customer's name when setting them up as a supplier instead of registering them under a different name, Evans. This way, you can keep track of both roles without any confusion.

So, if your customer's name is "Sample Only," you could add an extra letter like an "S" to create a distinct supplier name. Here's how to do this:

1. Go to Expenses and select Suppliers.
   
2. Click New supplier.
   
3. In the Supplier display name field, enter the customer's name followed by the additional character (e.g., Sample OnlyS).
   
4. Fill in the other necessary details.
5. Select Save.

Once done, you may use this resource to help you manage supplier refunds and credits: Handle supplier refunds and credits in QuickBooks Online.

Let us know if you have further questions by adding a comment below.