There is some spam protection build in and we only count delivered submissions. If you have any issue’s definitely reach out and we’ll remove any spam that gets through.
I don't think you're quite answering the question they've asked.
They want to know if you're doing any domain validation for requests sent to your URL, otherwise someone could quite easily eat up their quota by sending POST requests to the URL in the form.
There's no domain validation as we don't limit what domain or page your form can be used on.
If there was a malicious user abusing the service and they manage to bypass our spam protection then I'll definitely make sure they're taken are of as spam doesn't count towards your quota.
They want to know if you're doing any domain validation for requests sent to your URL, otherwise someone could quite easily eat up their quota by sending POST requests to the URL in the form.