From your question I understand that you want to use a SMS gateway, ie. an online service that allows sending text messages to mobile phones from the Internet - and the service you are using is rejecting your request.
There is no single, foolproof method of doing this. Depending on your phone provider and country, there may or may not exist gateways that will allow you to send a message. Some phone providers may offer such gateways on their own websites. Your phone provider is always the first place to look for such things. There are also third-party gateways, but they are generally subscription-based and paid.
Try to google for "SMS gateway", adding the name of your provider and country to search query, then look over the found websites, check their terms and conditions of use, and maybe you'll find a site that will work. There is no guarantee. The situation in this area is very dynamic and a gateway that worked a few years ago (which is probably used by your script "Text_T0_Phone.sh") may not exist anymore.
Here is one such service that I was using once; it is paid but offers free trial, which may be enough for you: https://www.world-text.com/
There is also another possibility - you need to buy an USB cellular modem, capable of sending and receiving of text messages, connect it to your computer and use software like Wammu to send messages from the modem to your phone.