Hi Shahzad,
Its continuous process, first you hired the proper regional language TSR’s then how to retain is the 2nd process, you always need the half backup for your total no of active operational seats.
Short List the Fresh University Gradates and provide training then hire the appropriate guys. Provide the healthy environment in your center .This approach should be in practice always then you have good CSR/TSR and Strong backup of Call center HR.
Saif