Good Morning @Susan10, thanks for your post and a very warm welcome to you!
Good advice from @enlli on this one, best option is to utilise Wi-Fi when outside the EU as some of the charges can be rather large.
If there is a spending cap set on the account, the service would not be available to use, once this cap has been hit.
So for example, if this is set to zero - it wouldn't be possible to run up any charges on the account.
Hope that helps clear things up for you!
Kindest regards,
David_Bn