I have a Tmobile SIM in my iPAD mini retina. I am using the 200mb free data plan. Immediately prior to heading overseas, I switched to a $20/1GB month monthly plan hoping to be able to get data in Europe. The iPad continued to show me on the free data plan (I assume because I had not yet used up the data and that data was to expire earlier than the monthly plan). Unfortunately, I couldn't get any service in Europe (Germany and Lithuania).

Any thoughts or advice for how to get this to work next trip?