Open your terminal and run these commands.
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
echo 'export PATH=/usr/local/bin:$PATH' >>~/.bash_profile
source ~/.bash_profile
brew install python 3
python3 -m venv my_env
Now download chromedriver here and put it in my_env/bin
source my_env/bin/activate
Modify config.py to put your phone number and phone provider in there. You can also modify the refresh rate but it may get blocked if you refresh too fast.
The arguments for the app are a month then days you are interested in. You will get a text message when one of the requested dates is available.
For example if you were looking for December 8th and 25th you would run:
python3 monitor.py December 8 25