A.M.
Hi M..
If he didn't pick the kids up on July 1, he has forgone his visitation. Period. That is the verbiage from a lawyer.
Now, on the other hand... you may want to be flexible and let him have them on the weekends that you don't have plans with them. Let him know when those times/days are and let him know that you're doing this for the kids. Maybe next year, he will know and pick them up on time.
Don't ever let the kids know that you're "battling" with their father though! None of this is their fault, so don't involve them and talk bad about their father. Always make them feel loved and always look at the positive side of things when it comes to them.
Good luck with whatever decision you make.
A. M. :)