PX AI Chatbot & Contact Form

I installed this app to try, but I chose not to keep it and deleted it. But it left code in my theme. The contact form still pops up sometimes even though the app is no longer installed. I cannot re-install the app as it fails to do so. UPDATE: thank you for your fast response and for the solution. I've done as you suggested and removed the leftover code so hopefully all is ok now.