Dan,
It looks like you are expecting your post to be read by Rick Steves. It won't be. This is a travel Forum hosted by his company but populated by a bunch of fellow travelers who are not affiliated with the company in way.
Some staffers do look in and make occasional posts but almost never on a weekend, so you are stuck with us loonies.
The best way to contact the company itself is to use the Contact Us buttons (email, phone, or a map to drop in) at the bottom of the page.
In the meantime, some of us are regular visitors to Paris, and some of us even live there or nearby.
It has been my experience here over several years that shuttle services, particularly prepaid shuttle services, have never worked particularly well in Paris.
There have been numerous accounts of different shuttle companies turning up very late, or not at all, who when chased have said that they were there and are keeping the money. The poor traveler then has to make instant other arrangements which sometimes mean they miss important connections.
It has been a long time since I have seen happy people here with anything other than the RER or a taxi, but almost all people are happy with the Air France bus.
You don't have to fly with Air France to use it.
Easy have just started Easybus which is unreasonably cheap if bought far enough ahead but there has been silence here from anybody who has tried to use it. It may not actually have started yet.
If I were in your shoes (I'm not, I'm happy with RER) I'd give the Easybus a bit of time to wear off the rough edges.
You can call the RS staffers on Monday (oops holiday - Tuesday) morning.