Passing email with PHP get

Hi folks

I was creating a dynamic form for a financial instance with +500 shops. Each shop has a different email.

Everything works fine, but when you add a point, everything goes wrong.

Example
http://gezondbeleggen.be/probeer/?khmail=test%40testmail%2Ecom
without a point: http://gezondbeleggen.be/probeer/?khmail=test%40testmailcom

Any idea or solution?

https://wordpress.org/plugins/contact-form-7-dynamic-text-extension/