T-Mobile customer service - Why did I call twice?

A T-Mobile customer for 10 years, and got snagged out of $79 !

I had an international charge on my Feb/March bill, so I called T-Mobile billing. The rep explained what happened, and offered two types of International plans sent to my text. She said she would block my “out of country phone” to ensure I wouldn’t be charged again. That way, I wouldn’t have to pay for the international plan(the phone would just be blocked to prevent more billing to incur). WELL - This recent bill comes in with the same charges! 

I called customer service again today to discuss my bill. The rep (Cyndi), explained to me how she thought this roaming charge appeared again. The rep from last month told me she had blocked something in the international phone but clearly didn’t know what she was talking about. Today, Cyndi told me to simply place the international phone in Airplane mode to prevent this again. 

Why did I have to call two times, and pay two months of extra charges? Note to self - “Call again tomorrow to verify”