How to Fix Internet Connection With centuryLink?

Okay i checked the centurylink website and my account says that i have 10mpbs on my Plan. It also says it in the bill i am paying for the 10mpbs high speed internet but when i check my speed at speedtest.net and other high speed internet tester it says that my speed is not even close to 1 mpbs. its says its below 1mpbs and my internet IS slow and its not 10 mpbs. So i dont know!! how to fix this!