Hi,
The ReCaptcha plugin that we provide can display a captcha on the contact form and reject the contact request if the captcha filled by the user is wrong.
It looks like you have it installed but there is no captcha displayed on that contact page.
So it could well be that you have the captcha plugin configured to display the captcha on the contact form but that it's not able to because of some customization of the contact view, but the check is still done and since the user cannot enter the captcha, the contact request is always rejected.
So try to deactivate the recaptcha plugin and see if that helps.
If yes, then it's a problem with either the recaptcha plugin settings or the file "contact" of the view "product" that was customized via the menu Display>Views.
If no, then the problem is elsewhere. It could potentially be another plugin, or it could be that your email server cannot send HTML emails, or emails with enbedded images, or emails with mutliple parts, etc. And you should check the Emails settings of the HikaShop configuration with your hosting company.