In our PortaBilling VoIP Softswitch, created rates or tariffs cannot be deleted from the customer or reseller tariff file. 
They are merely discontinued when you update with new rates.
A tariff file contains all the rates you are offering.
Each tariff file is associated with the product you are selling with your own markup rates.
You may view your current rates by clicking on your tariff file.
If you upload using the option "Replace all of the existing rates with the rates from the file", all rates in the tariff will be marked "Discontinued".
The rates from the tariff upload file will be added. Please ensure you are using csv format only.

The filter at the top of the 'Tariff rates' page allows you to view rates depending on their Effective From date or Destination.
The Effective From drop-down list allows you define whether only current rates (“Now”) or all rates ever used (“->Now”) will be shown.

Any tariff file that is currently used by an account cannot be deleted. You may delete the tariff file after assigning another product to the account.

Thank You.
Globalink  Support
http://support.globalink.us