Mock banking application including magnetic card reader

import csv
import datetime
import getpass
import os

full_date = str(datetime.datetime.now())
print(full_date)
while True:
        while True:
            while True:
                try:
                    ID = getpass.getpass(prompt = 'Please swipe your ID card. ')
                    if os.path.exists('.\Bank.csv'):
                        nukelanta_character = open('.\Bank.csv', 'a')
                        nukelanta_character.write(ID[1:10] + '\n')
                        print('')
                    else:
                        nukelanta_character = open('.\Bank.csv', 'w')
                        nukelanta_character.write(ID[1:10] + '\n')
                        print('')
                except KeyboardInterrupt:
                        continue    

I have many questions, but one step at a time. Sorry, I'm a network admin, but pretty unfamiliar with coding.
I have a banking application I am trying to make. It needs to be able to retain and update up to roughly 100 users and append existing dollar amounts.
I would like it to just state the number on the "credit card" (it's for a larp thing for fallout nerds {which I am one})
I'm waiting on a credit card reader in the mail, It really just needs to read the card's magnetic strip, offer the "banker" one of four options, "deposit, withdraw, view balance, and sudo (tbd)"
Currently I cannot seem to get it to append existing cards...
I would like it to be create/append entries so that someone can slide their card on the reader, where the banker will be behind the poc and enter one of the options mentioned above to execute...
Currently I have to "break" in order to save any of the data.
I have several tabs open for openpyxl, but...I'm kinda spinning my wheels.
Thank you all for your time.