Need a Database Administrator that have good knowledge of MSSQL

I have a High Volume transactions website and have issues in user accounting. USER Wallet balance Accounting issue due to the same time hit Transactions. when a user hit transactions at the same time (means same millisecond hit) by API some time my stored procedure take same opening balance for 2-3 transactions and made calculations.but calculation goes wrong due to same opening balance of 2-3 transaction.


Now I have made a job that run every hour and corrects user balance after transactions. but i want solution without any job.