You always have to check every bill, every credit card statement, every phone bill, and your bank statement every time you get them.
Same goes for hotel bills, bills for tires when having them changed, etc.
I use a hotel in one city that every time I stay there they charge me a dollar a day for the safe. I tell them each time that I didnt use the safe and take it off the bill. They do, but they try that stunt each time.
I have had another hotel try to slip 3 phone charges into my bill for $20 each. Got that fixed. A hotel in Seattle tried to charge me 3 times for watching one movie. Had to have the credit card company remove that charge from the bill when the hotel kept messing it up.
Stories go on and on about this kind of crap. Buy tires from Sears and they will charge you all kinds of fees you didnt authorize or want. etc etc etc.