Q: Support for Apple ID

Sorry, accounts cannot be merged.

To contact iTunes Support, go to: http://apple.com/emea/support/itunes/contact.html. You will get an email reply within 48 hours, often less.

Apple ID accounts can't be combined. Whatever you purchased with a specific ID will forever be linked to that ID.

You cannot combine / merge Apple ID's.  Your best bet is to stop using one of the accounts. Though any purchases made on it, will remain tied to it for ever, and cannot be transferred to another account.

There is no support e-mail address as such because the shear number of emails it would receive would make it unmanageable.

If you need to contact iTunes Support directly you'll need to follow the support path.

https://www.apple.com/lae/support/itunes/contact.html

They will contact you back via the e-mail address you supply there.

You're welcome.

Welcome.

You can have different accounts for different services.

There are 4 different services that you use with Apple ID accounts.

Settings->iCloud

Settings->iTunes & App Stores

Settings->Facetime

Settings->Messages

Each service can use a different Apple ID.

When you setup family sharing, you can specify an account used for purchases that is different to the account used for iCloud.

Use your own Apple ID for Family Sharing - Apple Support

This is perfectly fine. It would appear you specified the gmail based account as the one to use for purchases, so purchases are charged to that, even though you are using a different one for iCloud.