Years ago when she was going through a bad patch, she just wouldn't respond to anyone ever. This went on for about 2/3 years. I did have a lot of sympathy with what she was going through at the time and gave her her space.
Since then her life has really improved and she's really happy. She's still absolutely shit at texting back. I almost never initiate a chat with her now because she'll probably ignore it.
She text me randomly recently asking when she can come and visit (I live about 300 miles away from our home town). We had a couple of messages back and forth. She's left me on read again. The last message I sent offered some dates and also that I'd been hunting in the spare room for all the stuff she'll need for the baby so she wouldn't need to worry.
No reply.
So annoying!
(Yes I know no one owes me a response ever etc etc but she text me, she wanted to come up, and she has a lot of form for ignoring messages so it's not a one off)