This email is in response to your complaint/query received by the accounts department regarding delay in the salary. I apologize for the late processing of your salary for the month of __________ (mention month).
We have raised a query regarding your complaint and came to know that due to _______________ (mention reason for delayed salary) you had to face this delay. We regret the inconvenience caused to you.
I hope that you will understand the situation and forgive us for the inconvenience caused. I assure you that your salary will be credited to your bank account within _____ (no. of days). If you need any further assistance, you can contact me any time.
___________ (Contact details)