Contact Form sends email with my email in both the "To" and "From" section

Hello I am having the same issue with my contact form as this individual on this thread ( https://kriesi.at/support/topic/contact-formular-email-adress-error/ ) I tried to input the same code but it doesn’t seem to work, do I just paste it and the end of the function.php and save it and that’s it or are there some changes that I need to make on the Contact Form itself to reflect the changes? I have tried to start a thread but last time someone told me to contact my hosting service I have they have done absolutely everything they can and told me that it would be on your side to fix the remaining.