I would suggest adding a new feature to OsClass Pay where users can choose to “have virtual phone number”(proxy number) and they pay a fee to have this option.
Meaning that they will have a virtual phone number redirected to their current phone. This can also have statistics on how many calls they get, blocked calls, answered calls, not answered, etc.
Create a page with statistics for calls.
This would be an awesome addition to osclass pay and would decrease spam also giving website owners a new source of income.