The following is a service which telephone service providers (both landline and cellular) ought to provide their clients.
Whenever A calls B and leaves him a message “Please call me back”, it should be possible for A to optionally specify that the callback will be charged to him rather than to B.
Eventually, people will avoid calling back unknown numbers unless they are marked as “please call me back at my expense”.
This practice will eventually put out of business all fraudulent businesses, which thrive on getting people to call back numbers with very high rates.
Technical implementation should be relatively simple.
Whenever A sets the option to charge him for callbacks, the service provider will issue a random and for one-time use number, which B will use to call A back at A’s expense.