I've had a couple over the past few years, but it is rare that they don't post.

However ...

In February I went to one place where I was not provided with a customer copy of the bill. I didn't make a fuss at the time, but had the feeling I should have on my way home from there.
Naturally, my credit card was charged but no miles. I sent iDine a copy of my (edited) Visa bill, which the rep said would be OK.