The custom email address that I provide to 2Checkout/Verifone is intended to identify mail coming from them or their partners. I prefer mail from the ISPConfig.org to use a different address. What is the appropriate way to request a change of contact info like this? Thanks.
There is no such address. ISPConfig.org is not sending you any emails unless you contact them, and if you contact them e.g. for support or by subscribing to the newsletter, then you receive an email answer to the address you used to contact them.