I had a similar issue with comcast. I sent back a modem I didn't need, took photos and even had a receipt. After around 8 hours of phone calls asking them to remove it from my bill and them giving me the run around. They continued to charge me and sent my bills to collections.
At collections, it continued like this for months, I sent photos, I even had a recording of a comcast manager saying "we shouldn't have billed you, and will remove the charge".
After 18 months of fighting this $300 charge and around 30 hours of debates... I just paid the bill
You could just take the CEO to small claims court for the maximum amount in your area (usually $5000-$10000) for the charge + punitive. Some states make it so you can't have a lawyer represent you in small claims court, and since Centurylink does business in your area then the person you served (i.e. the chief executive) would have to show up in person.
That's basically what I did with a shady property management company (AMC LLC, one of the largest in the US tried to steal my security deposit) and won, but I've heard that huge corporations like CenturyLink will even immediately follow up with a settlement offer to avoid spending an executive's time.
I think in some states they can appeal from small-claims to non-small-claims court then you have to get a lawyer. Obviously a super pro-corporate court system.
A couple of Comcast employees were canvasing my neighborhood earlier this year trying to talk me into switching over from my amazing fiber provider. I told them I've read enough horror stories like this to ever even consider the possibility of getting into any kind of contractual agreement with them.
I had a similar fraudulent charge sent to collections once. I collected evidence and started a case to get it removed with the big three credit companies which basically took their teeth away. You can win without playing with courts.
At collections, it continued like this for months, I sent photos, I even had a recording of a comcast manager saying "we shouldn't have billed you, and will remove the charge".
After 18 months of fighting this $300 charge and around 30 hours of debates... I just paid the bill