Copyright notices and IP-related correspondence online

I am running an online business and wanted to know: if i clearly state in my website's terms and conditions that if any one wants to send a copyright notice to us or contact us for any IP-related issues, they should contact us online using our email address or an online enquiry form given on our website (not at our registered business adress) - is that ok? Because our registered business address service returns any mail that is not from HMRC or Companies House back to the sender. Would appreciate if you could kindly advise.

Also, if someone serves us a copyright notice at our registered office and that is returned to the them and then they do not contact us online either - should we be concerned about it at all?

Thanks.