Are Spammers Going to Kill US Toll-Free Phone Service?

I've noticed a huge surge in these silent calls to my toll-free number in the US, some spammer's way of making money from the dial around compensation fee (which appears to be unique to the US). At the current rate, it will cost me around $1200 extra per year, and I'm dropping my toll-free line as fast as I can (in about a year to switch my customer base and potential sales leads) before this scam becomes more widespread and the frequency increases even more. Will this mark the end of toll-free service, or does anyone have a way to identify and stop the dial around compensation fee from ever getting collected?

The spammers are using an enormous phone bank of hundreds of phone numbers, so there is no way I can black list them before they rotate numbers and effectively make an infinite list of numbers. My toll-free line is how new customers call me, so I can't white list callers. Simply making a connection for a few seconds inserts the dial around compensation fee to my monthly bill, so it is ineffective to just hang up. The toll-free service provider and the phone company are uninterested in helping me solve this problem.

This seems a pretty effective way to practically kill toll-free service in the US, for all but the most major customers of toll-free lines that can absorb this kind of scam as the cost of doing business. I can afford $1200 over a year, but the way dial around compensation is set up, there is nearly no limit to the abuse that can be dished out; it can conceivably increase an order of magnitude and I would still be paying the fees.