I just take it back to my carrier where I bought it. Assuming you didn't buy it unlocked somewhere for full price.
Or call them, they send me out a replacement and I ship my phone back when I receive their replacement.
I could never hit a limit with century link. They are my only option and my top speed is 1.5mbps. Yes thats right, its pretty sad coming from 60mbps and 100 before that. Only other option is satellite.