With Roam Like Home you should have been able to use your allowance to make calls and use the data included in your plan providing its one of the locations included in the RLH destinations list.
The fact you were able to make a call or text without being charged I’m assumed means that it came out of your allowance. Providing you had data in your allowance left and the settings in your account set to roam and your network on the handset set to auto you should have been able to use data.
Have a look at the Roam Like Home page here
And then have a chat with the online mobile chat team