Your choice of billing add-on unfortunately has no bearing on the roaming facility, which you needed to have texted ROAMING to 150 before leaving the UK to activate. It is this which enables access to foreign networks, without which you are now in catch-22.
Your symptoms - inability to connect to foreign networks - are as expected. Your only recourse now is to contact EE CS from another means, to request roaming is activated. Either from another working phone, a web-calling app or potentially a web-chat.
