My daughter was in the same position, there is a long thread on this is you do a search. My opinion, I would not pay any money upfront, my daughters house was removed from their database because she refused. There seems to be a very confusing situation on the CDS at the moment. many agents are claiming to be in a network (but I thought VIVA was the network). 2 of the agents she rang to list her property never got back to her. VIVA claim in their latest property supplements to be selling lots of properties since their commission cut eg. listed for 18 months sold in 1 week at low commission, but I think the reduction would be very small to shift a property of only 200,000 euros as the reduction would be small.
In the year that my daughters property has been for sale Viva have only brought 4 viewers a smaller agent at 5%commission brought 3.