AR customer linked to AP supplier

Summary

An AP supplier was auto-created when refunding an AR customer - how do I use that supplier again?

Content

We issued a refund to a customer for an over-payment, so Oracle created an AP Supplier in the same name.

Now I want to use that same AP Supplier to add an invoice and pay them by check. But the auto-created AP Supplier does not have a supplier number, and does not come up when searched for.

I really want to link these invoices within AP to the same Supplier. 

Is this possible?  If so, how?

Thanks,

Beth