DPs ex sees their children EOW. The break up was not amicable but DP is happy that the kids enjoy seeing her and they seem happy enough when they come home. The problem is when the kids are with her she messages vile messages him about how shit he is and he's a crap dad. This usually starts the day before she sees them and carries on until the day after as well as during her visit with the kids. Not even now and then....literally the whole time. In the beginning DP used to reply but stopped when he realised it didn't make any difference and it didn't deter her. At one point he blocked her and she just sent the messages to the kids phones! DP knows he has to keep some contact with her even minimal for the sake of the children and to make arrangements but this can't go on. It's mentally exhausting to be constantly hounded all weekends she has them. Is there anyone who has been in a similar situation who can suggest an alternative method of contact?