I am worried my sons aparents are not honoring our openness contract — what do I do?

There was some struggle when we wrote it as to how often they should send updates and photos(I wanted them more often, they wanted to send them less often) and I haven’t yet recieved the update for last month. I realize that they are busy and there could be a thousand reasons for them not sending it yet (it usually comes around the 25th of the month) but my concern is that they are just going to do it the way they wanted to rather than what we agreed on. Am I being paranoid and ridiculous? Is it possible there was a breakdown in communication and they are under the impression the agreement was what they wanted it to be? If so how do I approach the situation – do I ask for more frequent updates or do I just accept it as is?