The reason the fee was there was to pay for the 0800 thing. Some executive rightly saw that paying you to render that useless would free them of that service and the need for the fee (which i bet was not turning a profit) But, since big companies run on cargo cult... that happened.
I'm not working in real estate, but I'd guess that each referral would earn them at least something like $100 or much more - so forcing the "customer" (not really their customer since they don't sell anything to them, but only to the realtors) to call is the correct business decision.
The only WTF question is why they initiated a project that they don't want to use.