Problems after migration to a server with PHP 7

I asked my host service provider to migrate me to a new server with MySQL 5.6 and PHP 7.x so I could use WooComerce. But after the migration, my website stopped to load, when I try to reach it’s domain, my browser automatically downloads a “download” file. I’m not able to access wp-admin page either.

Website: http://www.kreemolab.com

(I’m using a reseller account from HostGator Brazil and I have another pages that are doing the same thing, but there are others that are working).