We hear this often. Yelp is like a mafia, it’s blackmail, etc. etc. etc.
While the list of things that Yelp does is quite certainly “questionable both ETHICALLY & MORALLY” – it is certainly not ILLEGAL! So our best advice is this… when they start asking if you’d like to start advertising with them – you need to act interested and tail them along – never say that you WILL NOT ADVERTISE WITH THEM. The second you do that – the employee unwittingly submits this info and the Yelp filters change to filter all your good reviews in response. Again, the employees don’t know their data they submit is used by the system like this – all they see is – “this guy said NO – next…”
When you have finally gotten the call, tail them on and never say YES or NO to them – just say – it’s not a good time right now, really busy, call back next month.