In the past Cash transfers using Venmo are not instantaneous and can be canceled after an initial transfer is sent. The transfers can take one to three business days to become final. Now Venmo says:
The moment you send a payment in Venmo, the funds are made available to the recipient. If you sent a payment to another user with a similar name, as a first step, send that user a charge request for the same amount of the payment so they can pay you back.
Vemo is really designed to be a friend payment system. Sharing this type of system with people you really trust.
Make and Share Payments
Pay friends and family with a Venmo account using money you have in Venmo, or link your bank account or debit card quickly.