"They immediately generated enough audio readings to max out the free tier"
It seems this is part of the automation, it got flagged based on this.
By the way, I am quite happy with JavaScript based spamfilters, they work quite well for small websites. The service Stop Forum Spam is something that seems fit for this, also at bigger scale. I assume Akismet might be good too, but it is somewhat leaky in privacy, depending on what you send to it.
It seems this is part of the automation, it got flagged based on this.
By the way, I am quite happy with JavaScript based spamfilters, they work quite well for small websites. The service Stop Forum Spam is something that seems fit for this, also at bigger scale. I assume Akismet might be good too, but it is somewhat leaky in privacy, depending on what you send to it.