the contact emails in the whois records for the domains you manage are there for a purpose: If there are troubles with these domains, the responsible people can be contacted in order to get the problems fixed.
And there is a good reason these whois data is not just a blob of Ascii, but structured data: Scripts can parse the records and e.g. automatically send email to the right address.
Getting back autoreplies stating basically “please use this web-form” is not going to cut it. We will not special-case our scripts to fill out web-forms just to accommodate your setup.
You, and your customers will simply not get our Mails regarding defaced Websites hosted by your service.
Your decision, your loss.