.txt file opened in python won't iterate properly

The following contains abridged version of the code for a text card game I am trying to run. It should get a random string for a card from a random line in "cards.txt", and add it to a user’s collection at "user.txt" (user would be the name of the user). A sample line from "users.txt" should look like:

X* NameOfCard

If "user.txt" already contains an entry for a card, it changes the number before the name by 1. If "user.txt" had:

1* Hyper Dragon

then got another Hyper Dragon, the line would look like:

2* Hyper Dragon

If there is no version already in there, it should append a newline that says:

1* NameOfCard

The code however, is flawed. No matter what, it will always change the contents of "users.txt" to:

1* NameOfCard
(followed by 3 blank lines)

I believe the issue to lie in the marked for loop in the following code:

from random import choice
def check(e, c):
    if (c in e):
        return True
    else:
        return False
username = input("What is the username?: ")
collectionPath = f"collections\{username}.txt"

while True:
    with open("cards.txt", "r") as cards:
        card_drew = f"{choice(cards.readlines())}n"
        print("Card drawn: "+card_drew)

    with open(collectionPath, "w+") as file:
        copyowned = False
        print("Looking for card")
        currentline = 0
        for line in file:
            # this is the marked for loop.
            print("test")
            print("checking "+line)
            currentline += 1
            if (check(card_drew, line)):
                print("Found card!")
                copyowned = True
                strnumof = ""
                for i in line:
                    if (i.isdigit()):
                        strnumof = strnumof+i
                numof = int(strnumof)+1
                line = (f"{numof}* {card_drew}")
                print("Card added, 2nd+ copy")

    if (not copyowned):
        with open(collectionPath, "a") as file:
            file.write(f"1* {card_drew}n")
            print("Card Added, 1st copy")
    input(f"{username} drew a(n) {card_drew}")

When I run it, the for loop act as if it’s not there. It wont even run a print function, though an error message never appears. After using try and except statements, the loop still doesn’t porvide an error. I have no clue why it’s doing this.

Some help would be greatly appreciated.