Advice plz - unreliable friends

What do you do when your friends only bother with you when they feel like it? They message me, I reply and then they take forever to reply and sometimes don’t even reply at all. They say they’ll let me know when they’re free and for some of them this means they’ll let me know in a couple of weeks and for others, I’ve been waiting for months and they still don’t let me know.

How do I discuss this with them?

If they can’t be bothered to meet then why bother to message me anymore? For the longest time I was the one putting all of the effort in and would organise meet ups etc. I then became distant because I could see it wasn’t being reciprocated. It makes me feel really frustrated, a lot of the time I feel like I am left hanging, wondering what I did wrong/if they are playing some sort of game. If they don’t want to be friends anymore then why do they keep messaging? I haven’t seen one of my friends since November and he said he would let me know when he was free but hasn’t. Sometimes he will message and say he hasn’t seen me in a while, he will have to let me know when he’s free and he just doesn’t. Things weren’t always this way, we used to go out a lot, I have no idea what has changed. In the past when he did agree to meet he would just spend a lot of the time on his phone as if I wasn’t even there.

When I meet up with my other friend I will ask about her life, how she is doing etc and then when I mention stuff about me she doesn’t even listen and just starts talking about something else. This makes me feel really alone, especially when I’m talking about my health issues.:

Anyway, what do you do in these situations? How do I discuss this with these people?