TLDR: is it my web builders fault the form submission feature doesn’t work and am I out of line to ask him to fix it?
Never hired a person to build a website and don’t know how to. Hired someone on Fiverr. Shorty after the website was made live, the website submission form where people fill out and request for a consultation (I work in home remodeling) didn’t work. The web builder fixed it, it worked for a few weeks, and stopped working. He fixed it and it’s worked for a good 8 months. Recently it stopped working, found out cause we stopped getting requests for consultation. Reached out to him and told him he needs to fix it. I used really firm language and told him that it’s unacceptable to me that this form doesn’t work and it’s costing us money.
He then asked me what is unacceptable? That things break and I am being rude and unprofessional. Esp after all the freebies that he gave us (I never asked for freebies). I told him that I didn’t know that things will break and I need to pay a monthly maintenance to make sure an important feature like the form submission form always work. I even told him that had he told me that things break and it’s best to pay a monthly maintenance, I would have happily paid the god damn $35 a month cause that’s nothing.
I guess my question is that is it true the form submission server error is “normal” and my request is unreasonable?

I’m betting your SPF/DMARC records aren’t set up. Since it sounds like you’re not technical, go and sign up to Brevo free plan and connect it to your site (with their plugin). You will need to make some dns changes.