Sometimes I want to speak with someone on the phone, but they are not available. So I send them a text and ask them to call me when they can, but you know I don't want them to call me and pay for that! So when they call, I reject it and call them back.
Well, this is the question. What can I say in my text? How can I make them understand that I just want them to call me so that I understand it's the right time to call them? What should the words of my text be?
It's frequently called a "missed call". They call you but hang up after only a couple of rings so the call appears on your phone as a "Missed Call from [number]" and then you can call them back.
I called you but you weren't available. When you are free, give me a Missed Call and I'll ring you straight back.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.