To clarify I texted to say:
Can you talk? Not urgent but had some bad news and would rather not text
I then had Lucy, A, J, Rebecca reply to say too busy to talk.
I then told the news as my job situation and added my job hunt was complicated by my health uncertainty.
I'm really sorry to hear your news, and how your friends have reacted. I thought from your OP that perhaps they hadn't quite known how to react by text, but you've pointed out you actually wanted to speak to them.
Personally, if a friend messages asking to talk, I tend to assume it's because something major has just happened and try to drop everything as quickly as possible to chat to them. I think it's quite selfish that your friends didn't do this for you, but I suppose I don't know how their own mental health is right now, and if they felt able to support someone.
There's a saying, 'put your own lifejacket on first' and being charitable, perhaps they have their own big problems and just didn't have the emotional capacity to be better. It's also possible that they don't have much experience of people dealing with cancer and/or they don't want to think about what it means, because you are actually very important to them.
From experience, when big, bad things happen, some people just don't know how to react. They don't.
Before you write off your entire emotional support network (they haven't initially covered themselves in glory, but you could do with a large emotional support network as you are going through a lot), I suggest you send a text blast along the lines of the following:
"I'm still reeling from the double whammy of losing my job and being diagnosed with cancer. I wouldn't know what to say to myself either, but I'd love to have a chat with you soon, as calling rather than texting is what helps raise my spirits. We've been friends for a long time, so please don't worry about saying the wrong thing; I just want to hear your voice as that will help me feel better."
If they don't make time to chat to you after that, then I agree that you may need to find some more sources of support, pronto.
I prefer to text rather than call, but a couple of my friends are the opposite. When I'm having a bad time, often they'll text me. When they're having a time, often I'll call them. You shift your own phone preferences when one of your mates needs you.
Again - because it hasn't been said enough - I'm so sorry you are having to cope with all of this that's been thrown at you. I really hope your friends step up soon and/or you find some lovely people to help support you IRL. I also wish you the very best with your treatment, and in finding meaningful work that pays the bills.
You're clearly in a lot of pain, but I think by posting here you're showing that you know what you need to feel better, and you should channel that into telling your friends straight what you need. At times like these, you should ask for what you need. And you should get it.