Sons account has been hacked and chat is impossible

My sons EA FC 24 account has been hacked.

I have spent countless hours on the chat with no success.

Although the game is still playable, the hacker has changed the email address and the ID.

I have attempted going through the EA chat 4 times now and it is proving impossible.

I have to many possible answers for their 6 questions and if I don't answer enough questions correctly then I get kicked out and told to try again.

The questions and my issues are - 

1. I.P. Address:

This one is simple enough

2. Last 4 digits of associated credit or debit card:

I have 3 possibilities for this

3. One purchase on your account (product name and date):

The only purchase I have that would count is the game itself but I am unsure if that was purchased through my PS account or my sons. I have bought him FC Points but this purchase doesn't count for the security process.

4. Date of birth:

This one is problematic as, due to his young age, I may of just made something up.

5. Billing Address:

Simple enough

6. Phone number.

Again, problematic as I may have put my number, my wife's or my sons.

This process is impossible and I am worried that I will have to stop him playing this and all future EA FC games due to the account being compromised.

I am at a complete loss of what to do.

Why cant a security code be sent to the original email address or the originally linked phone number.  

Its like EA has no plan b and the chat assistants are not allowed to use any common sense. There is no way to speak to anyone and there is no complaints procedure. I'm paying hundreds of pounds every year for EA products and coins etc. and the aftercare is non existent.

Any advise will be greatly appreciated.