Comment Re:What company (Score 4, Interesting) 451
Why not offer two "phone gateways" for your support? One for customers with existing support contract, and another for those without.
For support contract line, have a robot switchboard system that requires a valid support contract code. All other callers would have to go through a premium rate number. Sure, it adds one extra step for customers who have contracts but they probably don't need to call you too often anyway.
Keep the distinctions clearly visible in your help screen. The premium rate probably discourages useless support calls, and those who perceive a need for more frequent support can easily crunch the numbers and decide which option they prefer.