We've all heard horror stories of tradesmen causing chaos: "I asked them to fix a tap, but after the sink broke we had to move out for 6 weeks while the carpet was dry-cleaned and new floor-boards were laid." This problem generally occurs after you have let the supplier have a free-for-all in your house while you're at work: "Just let yourself in, the keys under the mat, and get the job done".
My Father-in-Law is Greek and I have noticed he gets more out of a tradesman than anyone else. Bottom line is he watches what they're doing and then gets on their case early when things aren't perfect. Whether it's carpet layers not matching the patterns together or plasterers leaving unsightly corners - as soon as he spots a problem he confronts them straight away and gets them to rectify it.
With any professional consultant or tradesman you should always take a hands-on approach with the project, stay on top of the important issues, and be ready to get involved when you see a problem.
Of course, as your relationship builds with the consultant or tradesman, and they become more aware of your expectations, you can divulge greater trust and leave them to it.
So you should insist that your software consultants maintain verbal contact with you (before resorting to emails).
They should then use “as per our conversation” follow up emails.
Tip: A nice way to know what is going on is going on is to turn up to the daily scrum.