Fix Firebase Contact Form Issues

I have a personal website where I show my photography and take enquiries. There is a contact form on it with name, email and message. I connected
it to Firebase myself with a youtube tutorial because I wanted everything in one place instead of in my mailbox, and I was quite proud of it until I
looked properly.
Two things are wrong:
- in Firebase there is always only one message, every new one takes the place of the last one
- when you press Send the page jumps to the top and nothing else happens, so people send it two or three times
The second one I could live with. The first one I cannot, I have no idea how many people wrote to me and got lost.