Notification if customer changes Data (adress invoice or delivery)

Hi,

While the user can manage the billing and shipping addresses linked to his account, when he goes through the checkout, he has to enter/select one billing address and one shipping address for his order.
Once he clicks on the "finish" button of the checkout, the order is created with the provided billing and shipping addresses, and after that, the user can't change the billing address and shipping address of an order. Only the merchant can do it from the backend interface. Even if he changes the same address linked to his user account, the address in the order won't change.

Are you saying that you want to be notified when someone modify his addresses linked to his account ? Could you tell us why you need to do that ?
You could create a mass action of the type "address" with triggers "after an address is updated" and "after an address is created", and with an action "send an email". Then, you would need to customize the "mass action notification" email via the menu System>Emails and customize the "HTML" to use PHP code to display the data available in $data which will contain the information of the address.
So it's technically possible to do it, but it requires a bit of coding in the email.

Hi,

In this case the customer takes the order in his own ERP System and if the customer makes changes they don't know, the will use the wrong data.

Well, normally, the billing and shipping address of the order is sent to the ERP when the order is created. And the customer cannot change these in the order. So there shouldn't be any need to send an email because the customer can't change that.
That's why I don't understand what you're trying to do.
The only case where the address in an order would be changed would be if the administrator would change the address of the order from the backend. But in that case, I don't see why an email notification to himself would help in anything.

BTW, I really need your help and need support for my other project, I tried really hard to get in contact with you. Can you please help me in this project too?

I did some investigation and I can see that there were some spam issues at some point where our email provider flagged you as a spammer and I missed your messages.
I'll send you an email from another email address. Hopefully, it should work better.