It sounds like your rates are "non-contract", as in just the maximum tariffed amount allowed in your state. Many times, people will select a carrier for their long distance, but not notify the carrier that they want to do business with them. In non-contract situations, carriers treat this as "casual" use and bill accordingly.
As for the hunting, no traditional phone systems do not, and cannot provide hunting, regardless of the brand. From the rates you are paying, it appears that you don't have ISDN lines. A phone system with ISDN is the ONLY way that hunting can be provided by the phone system.
The interstate access charge sounds like a federal tax that is levied by all carriers under law and doesn't change from carrier to carrier. It's also known as the Federal Subscriber Line Charge.
The rate for DSL sounds appropriate for a business account.
The Advanced Data Services charge isn't clear to me; it could be anything.
As for directory charges (I assume you mean directory advertising), are not regulated by the state. If you elect to dispute them, you should still pay the regulated portion of your phone bill to avoid the risk of your service being disconnected due to non-payment.
You should consider switching to a competitive local exchange carrier (CLEC) that may offer a bundled package that includes all of your features with a block of long distance minutes included. Even cable TV companies have this available now, so leave no stone unturned in your quest.
