I have the same form on the contact us page and it looks just fine. The mobile also looks fine too. It’s just on this page that the border gets cut off.
Actually i found out that the following CSS code you have used in your inquiry form is causing the issue. We can’t change this CSS developing other custom CSS code as you are using the form in iframe tag.
@media screen and (min-width: 500px) and (max-width: 850px) {
#mainFieldWrapper {
width: 550px; margin-left: 10px;
}
}