Unblocked contact but still can’t text or call

I blocked someone a year ago and recently unblocked them. She can’ text me but when I reply, my text will not deliver or her. She can call me also but when I call her, her phone doesn’t ring and goes straight to voicemail mail. Also, she never blocked me so the issuer is on my end.

I’ve don’t the following:

1. unblocked her in all places, Facebook, text, phone, messenger. We can message on messenger but that’s it.
2. deleted her as a contact and re- entered her
3. ive updated my iOS to the most recent version thinking that would fix it
4. i deleted her contact again, then turned my phone off. Turned it back on re- entered her

what am I missing?