Once a Spot registered cell number payment goes through successfully, it cannot be refunded or cancelled. If the number you sent cash to isn't registered with Spot, those funds will be credited back into your account within 7 days.
The only way to get the funds back from a registered number is to ask them for the money back. You can send them a Request Pay, give them a call, or send them a text.
Pretty please (with a cherry on top) always double-check that you’re sending money to the right friend before confirming the payment.