I want to let you know that most of the links provided from your list doesn't direct you to the site mentioned. You can copy the quoted post below for the working shortcuts. The quotation mark you added and the duplicated http what made the links incorrect. I would like to suggest bitrefill to be added in the list i've used their service a couple of times when I need airtime for my phone and they also give out refunds when your request doesn't get processed in time.