Why am I charged monthly rental even after getting NOC for my service number, even though my service is terminated?

Why am I charged monthly rental even after getting NOC for my service number, even though my service is terminated?

When we purchase any Tollfree or Premium numbers from the operators, we pay the rental for those numbers to the operators every month.

After providing the NOC to the client after service termination, we still keep on paying the rent to the operator to keep the number active till the ownership is successfully transferred to other vendor or service provider which is porting in the number.

Also, there is an expiry date to the NOC we provide to you. So it is advisable to get the ownership transferred within the time period or before the expiry date of NOC else monthly rental will be applicable as number holding charges.

Also would like to inform you that after the ownership is transferred to you, you will have to make the payment to your operator directly as well to keep the number active.