Phantom Data Charges on a phone with no data!

at 80 dollars a month, fido has the most expensive 25 dollar plan available. I signed up for the month-to-month plan for 25 dollars, and now for the 2nd month in a row, I am getting billed for data i didn't use! (i use a software-side block for all data, since fido told me they "couldn't and wouldn't provide me this service.) Isn't it amazing that after blocking all data to my phone, i have now spent nearly 50 dollars on phantom data? God I cannot wait until telus goes gsm. I expect someone to contact me back, and not have to go through a phone tree. Something also of interest: upon searching, I see there are at least 5 other such complaints. This is beginning to look like corporate "catch us if you can."