Long story short: in December 2020 we met online and fell in love and had a LDR in 2021. Even though we're very compatible for eachother (personality and opinions and interests and more) , things didnt go well and she lost feelings and has been going offline more and more. She has bad mental health and said that it is not only me but that she just wants to be alone and not have to deal with friends or anyone at all.

Currently: at any random day I could suddenly receive a text from her, which if i'm online to respond fast enough results in a conversation that lasts a few minutes and then usually she goes offline again, not even saying bye, and then it takes a few months until I suddenly receive a text again. This has been going the last 1.5 years. She is almost non-existent on the internet.

Now I have no clue when she will be online again. It could be today, tomorrow, in 3 weeks, in 3 months..... But when she is back to talk to me for a few minutes, what kind of things am I supposed to tell her? I think that she already knows I miss her alot because I've been telling her that often. She also hates it when I ask questions and doesnt understand that having answers to some questions is really important to me.

But since the next time she comes online to talk to me it will probably last only a few minutes again... how do I use those minutes efficiently to have a great conversation, to give her a good time, to maybe convince her to talk to me more often again? What would you guys say in that situation?