I changed my Apple ID to a new one. The old account was a hotmail account with a icloud associated email address. The new one is gmail with an associated new iCloud email address.

I was on a support call with Apple at the time of the change and they permanently deleted the old iCloud address and walked me through switching to the new Gmail address. I subsequently set up a new iCloud email address that is associated with the new Gmail address. However, for some reason, inbound emails to the old iCloud address are routed to the new iCloud email mailbox that is associated with the new gmail Apple ID address. When I login on my iPad or Windows desktop to iCloud and look at my mailbox, the emails sent to the deleted iCloud email address are posted. I need help understanding why? I made the change because I was receiving weekly hundreds of absolute garbage emails and wanted to put a stop to all the unwanted emails. Any help would be appreciated.