You will need
  • A copy of the payment order that contains the error.
Check with your Bank held the payment or not. If the money is not transferred to the account of the "wrong" contractor, send a letter to the Bank asking to withdraw a payment order. The money will remain in your Bank account.
Compose and send a letter to the contractor with a request to return the money if the Bank already transferred money from your current account to the account of the counterparty for that payment. Let me know the details of your organization. Attach a copy of the payment order.

The counterparty is obliged to return the money within 5 working days. By its refusal to return the wrongfully obtained funds, you will have to sue him in court.
Compose and send a letter directly to the Bank with a request to return the erroneously transferred money, if your payment document everything correctly, and the amount transferred to another company in the result of an error of a Bank employee.

After receiving your letter, the Bank will notify the recipient of mistakenly transferred to his account the amount. After receiving the notification, the counterparty is obliged to transfer this amount to your Bank account within 3 working days.
Notify your employee in writing in case you mistakenly transferred the funds to his Bank card, overpaying wages. Get your employee's written consent to the making of the overpayment to the cashier and take his cash on cash order, or issue an order withholding from his salary excessive payments.
Apply for the mistake to the tax authority at the place of registration, if you find an error in the transfer of funds to the payment of taxes in budgets of the Russian Federation. Attach to the application a copy of the payment document confirming payment of the tax. The tax authority can be carried out the joint reconciliation of taxes paid.

Unduly listed sum you will either read on account of forthcoming payments under this tax, or will return within one month from the date of receipt of the application by the tax authority. Keep in mind that if your organization has tax arrears, penalties and interest on that tax, then the check will be deducted from this amount.