When settling with several people at the same time, it can sometimes be unclear that you are settling Steven account to Steven account. If your balance is too low, you can top up using Swish or Klarna in the same flow, and this is sometimes interpreted as being a 'regular swish'.
The money is in the recipients Steven account, which is found under the Account tab of the bottom navigation. They can use the money to settle future debts, pay with the Steven Mastercard, or transfer the money back to their bank.