T-Mobile Number Existence Scraper

I need a small Python utility that signs in to https://account.t-mobile.com/signin/v2/ and tests a list of phone numbers one by one. When a number is valid the page immediately switches to the “Send OTP” step; when it is not, the site returns “We couldn’t find that phone number.” The script’s only job is to capture that response and sort each number into the right text file: exists.txt for the OTP prompt and non_exists.txt for everything else.

I want to be able to launch the program from the command line whenever I choose, yet also drop it into a scheduler (cron, Windows Task Scheduler, or a simple built-in timer) so it can run unattended at set intervals. Output should stay on local storage in two clearly named files plus a concise run log so I can trace any errors.

Deliverables
• Clean, well-commented Python 3 script
• Simple README explaining manual run, basic config, and how to enable scheduled runs
• Sample input file format and the two output files generated after a test run

Acceptance criteria
– Numbers are split correctly based on the site’s response text.
– Script exits gracefully if the site layout or wording changes and writes an error to the log.
– No external services are required beyond standard Python libraries and one headless browser driver (Selenium or Playwright are both fine).