Can I stop messages from text apps?

This might sound dumb, but I just don’t know new technology. I broke up with my ex and while I tried to keep it friendly but firm it seems like he misunderstood the whole thing and tried to get back with me. I ignored him, blocked him on everything, and now I’m receiving all those stupid messages that I believe are from a text app. I tried googling the numbers and nothing comes up, he’s the only one who would send me stupid shit like this, and I know for a fact that he’s been using those text apps because his ex used to block him and he tried to get in touch with her (supposedly about the kids). I can’t just block unknown numbers because this is my work phone as well 🙄. Can I do something about this? Just ignore and hope he moves on?