Virtual Sim card Tech for cell phones and payable services with cryptocurrencies -Blockchain VOIP

Talked about this for a bit and I would love to put the idea in action! overseas i bought what is called a MIFI hotspot and with this device I can travel anywhere in the world and pay for internet service, which to me is fantastic. The best par is that no Sim card is required to use the service, you just buy data for what country you are in and BAM! you have service. I would like to gwt help with financing development of an app that would use already existing tech in our phones to speak with the towers and allow customers to buy voice and data with cash or crypto. If not that then develop an app that works purely off wifi for voice services payable only with crypto. Fact is we all see it and crypto is the future. What I am proposing is that we build a VOIP service that works on the blockchain. customers provide no real information and so their calls and information would be kept personal. If anyone has a take on this let me know, because I am all ears!!