My daughter complains of a little boy kicking her under the table and this year he sits right across from her for the next 4 - 5 weeks. (Previously)I have seen this little boy embrace her and nearly pick her up in excitement.
She has also complained that another little boy is mean to her. I don't even know the details of that complaint because I don't get involved unless there is an actual fight. The little boy that was mean to her saw me in after school care and told me he had a game...a soccer game...it was tomorrow...and my daughter told him that she plays hockey. Okay, so they talked about their sports it couldn't be that bad. Yesterday, I walked up to the little boy and asked how his game was and he told me it was really good! They won! They played the older boys and still won! [High five]
I waited for a reaction from my daughter for talking to him and there wasn't one.
They are kids and kids do things to each other, like kick, poke, and say mean things, hug, help, talk sports, and more, so it all changes very rapidly. There really isn't much need for adult intervention at this stage. Help him remember that no one appreciates getting kicked because it hurts.
So what I said about the kicking was, move your feet somewhere else and if it continues, tell the teacher. They usually like to observe behavior like that because they are aware the kids are getting used to sitting still in a group setting. Watch him when you are sitting next to him and if his feet start swinging, remind him that he could kick someone and hurt them.
Everyone is learning to get along with others, even the dad that called the school.
Don't beat yourself up over it, it really isn't a big deal. Keep teaching him the golden rule and it will work out just fine.