How to stop Zoho Creator sending us spam mails?

How to stop Zoho Creator sending us spam mails?

We keep getting spam mails every few days from a Lee Joseph (lee@zohocorp.com) who won't take No for an answer, instead he keeps sending out spam mails several times a week.

Having already gone through a poor customer service experience with Zoho Books, can someone please stop Lee from sending spam mails please, we don't use Zoho Creator, nor will we use Zoho in future projects! Thanks.

Juergen