Step daughter issues

So about a year ago my step daughter (7 at the time) told a lie that me and her dad beat her and abuse her. Her mother didn’t say anything to us and called child services. There was an investigation and court and nothing was founded and everything was dropped a month later... but the mother refused to let my husband see her and my husband was scared to see her because of the lies she was telling. So a year goes by... we’re having another baby.. the DAY I have our baby the mother messages my husband out of the blue saying congratulations and he can see his daughter again. How weird right? So of course my husband jumps at the opportunity. The day after I have our baby she comes over after a year of not seeing or speaking to her and things went... ok for the most part. The second time was a little rough. She gets upset when I yell at my other children (obviously when there doing something bad) and says it’s abuse! I really don’t want her to come back over but my husband obviously dose witch I completely understand but how can I tell him I don’t want her here? I’m so scared that the same thing is gonna happen again and I’m not over what happened before! I don’t want her poisoning my kids minds saying yelling or time outs are abuse... I really don’t know what to do about these feelings I’m having about it. I feel bad for feeling this way but I cant help it. I hate worrying if she’s gonna lie again and have the cops at my door again and child service investigation on me again I feel like I shouldn’t have to live in fear of my step daughter

She’s been in therapy for almost a year and we all have tried explaining the difference between the two and either she dosent seem to get it or she’s using the abuse line to scare the parents because apparently the mother is scared of the little girl doing the same thing to her. My step daughter has called my husband recently in tears saying her mom is scaring her. So I don’t know. The mother is crazy herself and there is no reasoning or talking to her.