majd900 on "Getting a Fatal error: Call to undefined function whenever i visit my site!"

Hello WordPress Forums!
so i'm having this problem that started today when i wanted to add a custom field in my checkout page but when i did that, whenever i visit my site it shows this "Fatal error: Call to undefined function bazaarlite_get_logo() in /home2/majd900/public_html/wp-content/themes/bazaar-lite/header.php on line 30"
I tried to reinstall all the files (except wp-content and wp-config)
didn't work
I searched over all the web and i didn't find any single solution :(
Anyone knows how to fix this?

I edited my checkout page in the appearance > editor i added a code that i got from youtube where i can change the additional notes placeholder and title.
so after i got this problem, i deleted the code from functions.php and the code from the editor.
didn't work

UPDATE:
I just found out that i made a huge mistake when i added that code!
I should have added the code to bazaar-lite-child not the normal bazaar-lite!
but i still dont know how to fix this yet

[Moderator note: Please stop bumping. Your issue isn't more important than anyone else's]