"The dad" trying to confuse my daughter...advice please!

Hey fellow single parents! Sorry if this is long, but I would appreciate any suggestions or advice any of you have to give me.

My 4-year-old saw her dad yesterday, and it seems he's always trying to put things in her head and confuse her, as a means of getting back at me. He hardly sees her and it's just wrong that he chooses to act childish instead of actually spending quality time with his daughter. For instance, when I had my daughter I hyphenated her last name so that it has both mine and his last name, assuming that he would actually play a dominant parental role in her life. Things ended up differently and she is raised by me and my family. She hardly ever see's him or his family, and was calling him by his first name until about a year ago. So now that she's in school, she is learning to write her name, and she uses just my last name. I never explained that she has two last names because I didn't want to confuse her or make her feel "different" in my family. Of course I planned on telling her, I was just waiting it out. Well he decides to beat me to the punch, and when she shows him one of her school papers with my last name on it, he was offended and started drilling it into her head that her last name wasn't mine, but his. Later that day after I heard what he did, I of course sat down with her and tried my best to talk to her about it in a healthy way, that she has 2 last names, one from me and one from her father.

And yesterday, she saw her dad for the first time in about a month. So today out of the blue she says, "my dad said he's going to marry you, and that he still loves you", etc. I didn't know what to say, so I just told her "next your dad says things like that, tell him you don't him to talk like that to you." I don't even know if she understands! And it shouldn't be her job to confront the issue, but he won't listen to me! He's done this before and now that she's getting older, I just really don't know what to do about it. He also tells her that I'm mean to him, and that I don't let him see her (which is NOT true. Even though sometimes I'd rather him not be around at all instead of showing up every now and then, she loves him so much and I wouldn't ever deprive her or him of the right they have to each other). I'm never around when he says these things to her, so it's not like I can do anything, plus I've already told him when she was not around that she tells me the things he says and that he needs to stop. He doesn't listen, he has no respect. And it just makes me feel uncomfortable. I don't know how to explain the situation to my daughter, or how to help her understand why me and her dad can't be "friends". I don't want to stooop down to his level and start pointing fingers to her, because I would never want to put her in the middle, or make her feel like she has to choose.

What would you do? How would you approach the situation, to both my daughter and her dad? It's just going to far and at this point, I don't know what to do.

My ex does something similar. Not to that point though. I was told to record talking to her about what she says, or have a witness (non family member) or two witnesses to it. Then take it to court. If he won't stop with you telling him, then have a judge do it. That can seriously screw with their head sweetie. It needs to stop NOW before you cant repair the damage.

Thanks for the advice. I am definitely going to start recording it!