My sister is accusing me of sleeping with her husband

So to try to keep this short I’ve been doing onlyfans for about a year. Started off just trying to make quick ends meet money then got lucky and it’s my full time gig now. My whole family knows what the deal is and never really bother me about it since majority talk to me on Facebook anyway which I keep civil.

Well my sister has been going through her own marriage drama. Last time we talked she said she was leaving her husband due to she found out he was still fucking his baby mama, lying about and etc. She asked if I was willing to let her move out with me since she’s pregnant and can’t deal with the stress, I said sure and then she went silent. I tried texting/calling got ignored for about a month where she would say she was busy until I just got this message asking if I ever fucked her husband. I said I no and asked why. She immediately went into how I am nothing but a lying hoe and she saw on his phone that he subscribes to my onlyfans. Then for her “proof” that I wanted him mentioned how when we were in high school I said he was cute. Mind you, we’re 25 now and I know for a fact he isn’t shit. Plus to top it off I’ve lived out of state for almost 2 years now.

How do I reply to this? Or should I?

I tried calling and keep getting hung up on.