Your post advocates a

( ) technical ( ) legislative ( ) market-based ( ) vigilante

approach to fighting robocalls. Your idea will not work. Here is why it won't work. (One or more of the following may apply to your particular idea, and it may have other flaws which used to vary from state to state before a bad federal law was passed.)

( ) Telemarketers can easily use it to harvest phone numbers
( ) Distributed phone centers and other legitimate spoofing uses would be affected
( ) No one will be able to find the guy or collect the money
( ) It is defenseless against brute force attacks
( ) It will stop robocalls for two weeks and then we'll be stuck with it
( ) Phone users will not put up with it
( ) AT&T will not put up with it
( ) The police will not put up with it
( ) Requires too much cooperation from telemarketers
( ) Requires immediate total cooperation from everybody at once
( ) Many phone users cannot afford to lose business or alienate potential employers
( ) Telemarketers don't care about invalid numbers in their lists
( ) Anyone could anonymously destroy anyone else's career or business

Specifically, your plan fails to account for

( ) Laws expressly prohibiting it
( ) Lack of centrally controlling authority for telecom
( ) Open relays in foreign countries
( ) Ease of searching tiny numeric space of all phone numbers
( ) Asshats
( ) Jurisdictional problems
( ) Unpopularity of weird new taxes
( ) Public reluctance to accept weird new forms of money
( ) Huge existing software investment in telecom infra
( ) Armies of phone banks
( ) Eternal arms race involved in all filtering approaches
( ) Extreme profitability of robocalls
( ) Joe jobs and/or identity theft
( ) Technically illiterate politicians
( ) Extreme stupidity on the part of people who answer robocalls
( ) Dishonesty on the part of telemarketers themselves
( ) Network costs that are unaffected by client filtering

and the following philosophical objections may also apply:

( ) Ideas similar to yours are easy to come up with, yet none have ever
been shown practical
( ) Any scheme based on opt-out is unacceptable
( ) Blacklists suck
( ) Whitelists suck
( ) We should be able to talk about Viagra without being censored
( ) Countermeasures should not involve wire fraud or credit card fraud
( ) Countermeasures should not involve sabotage of public networks
( ) Countermeasures must work if phased in gradually
( ) Calling people should be free
( ) Why should we have to trust you and your servers?
( ) Incompatiblity with open source or open source licenses
( ) Feel-good measures do nothing to solve the problem
( ) Temporary/one-time phone numbers are cumbersome
( ) I don't want the government monitoring phone calls
( ) Killing them that way is not slow and painful enough

Furthermore, this is what I think about you:

( ) Sorry dude, but I don't think it would work.
( ) This is a stupid idea, and you're a stupid person for suggesting it.
( ) Nice try, assh0le! I'm going to find out where you live and burn your
house down!