You could give it a try and create a Billing ticket for such case. You’ll need to follow these directions here:
I am afraid Cloudflare Registrar doesn’t allow refund, per ToS:
SECTION 4: FEES
4.1 FEES
Registrant shall pay Cloudflare the fees specified in the Order Form. All payment obligations are non-cancellable and non-revocable, and all amounts paid are non-refundable.