I used to advertise on Viva street. You get a huge volume of calls but many of them are hagglers, time wasters or no shows or their english is so poor its impossible to give them say directions etc. My advice is perhaps have a seperate viva street phone so you know when they ring they will have zero info really as you can't put rates or services and if they sound at all dodgy just say you can do a half hour as like I say you will get a fair few no shows and you don't want to be booking them in for hours and turning down genuine clients.You will also get alot of late night callers, I mean at all hours.
I stopped advertising as overall I think its quite expensive for what it is and the constant stream of idiots you have to put up with on the phone to actually get a few proper bookings can start to get on your nerves. Now and then they do offers of a months free advert and thats when I go back on.