Text messages going to my ipad and not my android phone

I'm not very apple literate and use an iPad for work. Somehow messages from only 1 person have been going to my iPad and not my android phone. What is really weird is I have a Note 9 and can get texts from anyone except one person. Those messages show up on my ipad. I never installed iMessage on my ipad and this happened out of nowhere with it being installed. I have disabled imessage under settings and now I cant get messages from that one person. They have an iphone11. What's even weirder is it only happens s on Thursdays. My ipad has a completely different cell number than my phone.