The wording of “I want to send you money” text that shows up when you go to the “Send money” tab seems a bit off - to me it feels like the kind of thing that would be sent in a spam email, trying to get bank details out of someone. When I sent messages to people I had to paste over the text every time. Perhaps rephrase it? Although this is obviously a direct message, but I think that not all people would realise that the wording of this message in this context makes it more genuine - rather, I think that for most people would just trigger the “spam, delete it” filter in their brains.
That’s really great feedback, thanks @duncang! Would you mind sharing what you generally change it to? Maybe we can ‘borrow’ some of your words 
I told quite a lot of people about the app already, so I was able to reference those conversations. Of course, that’s not generalisable as some people won’t have had those. But perhaps the text could walk the line between the two. It’s actually quite hard to phrase because it requires both a one line elevator pitch that your mum would understand, and being general enough in phrasing, tone, etc. to be sent by anyone (I recently found out that people much younger than me laugh at my generation for using the word “cool”, in much the same way that we thought the cringeworthy “groovy” was ridiculous). In a lot of my messages I said that I could potentially bump them up the waiting list, as I think that was mentioned here on the forums. The perception of scarcity is, of course, enticing. So, putting that all together, perhaps something like:
"I joined Mondo, and I think you’d love it too; they have a whole new take on banking. I can bump you up the waiting list if you sign up!“
or
"I joined Mondo, and I think you’d love it too; they’re rethinking banking. I can bump you up the waiting list if you sign up!”
Of course, you’re probably best to come up with a number of these and A/B test them to see the response rate.