I use facactum (?) last year, for a week it cost me £149.
the emailed me all enquiries with the daily results. I think I had it set so they answered in my name and apologised that I was on holiday for a week but they could take a message and I would return all calls when I got back
I think I only had them answer from 8am 6pm with an answephone outside those hours.
I returned to 21 calls to call back, normally I would get 30ish in a week so it did not work as good as me answering...... but not bad