SPOKANE, Wash. -

The Federal Trad Commission announced Wednesday that it's suing T-Mobile for allegedly overcharging customers on their wireless bills. And it can be easy to overlook bogus charges on your cell phone bill, so the FTC is sending out some tips to make sure you don't get scammed. 

The FTC opened the lawsuit against T-Mobile, saying they were billing customers for services they never used or authorized, such as celebrity gossip and horoscope text messges. T-Mobile put the blame on third party vendors and said the allegations were unfounded. 

But it's more common then you think for wireless customers to get phony charges. It's called "cramming." That's when companies add extra charges of varying amounts on your bill. It all seems legitimate, but it's actually not. 

So, the FTC is now offering some tips to make sure you don't get scammed on your next bill. 

First, they say to never enter your phone number on unsecured websites. You don't know who that number is being shared with and what they'll do with it. 

The FTC also says that any unsolicited text messages could be a sign you're being billed for a service you didn't opt into. The agency says to look closely at your next bill and make sure there are no new charges. 

And if you spot a charge for $9.99, look at it closely. That's the most common cramming charge, and it often goes overlooked. 

According to the FTC, if you don't know what a charge is for, call your wireless carrier. They should be able to provide you with more information about what a charge is for.