my bill

hi
So I had called to advise I would not be using my phone to make any calls as I would be out of the country and only wanted wifi services. I was advised to have the passport plan for 30.00
I now see I am still charged my normal 85.00 Plus the 30.00 this makes no sense to me.
If I was gonna pay more money to use the phone less it doesn't make sense to have this plan! I was told it would only be the 30.00 a month..not my normal bill plus 30.00
Please let Know how to get this fixed

Thank you
Mandy