T-Mobile iPhone 5s Cellular Network Not Working?

So I have been unable to use my data at all even when I was on my previous iPhone 4 even though it had full bars and the 3G logo at top. It's weird because it worked perfectly fine months ago everywhere I go. I'm not sure, but I think it might be something in the settings or that I dropped my phone.

Now that I gotten the new iPhone 5s, I still have no data and I end up using Wi-Fi even when it is saying I have full bars and has the LTE or 4G logo.

How could I fix this? Something in the carrier settings?

Settings > Cellular > Cellular Data: ON > Enable 3G: ON

That's all and you'll have data on your phone.

Go to your settings and make sure you do not have data restricted to Wi-Fi only.

Know that using Wi-Fi is GOOD! It means you are not using cellular data, which is usually limited. I know that with T-Mobile, you get 500 mb of cellular data and then the rest is slowed down (unless you purchase additional data). Using the Wi-Fi saves your cellular data for when you need it (and you may be able to not purchase additional data if you can use Wi-Fi most of the time).