How amenable is CenturyLink to covering an address outside of their normal service area? (Or, getting internet connectivity to middle O nowhere)

I have a remote office in the middle of WTF-nowhere that has zero options for wireline internet service. Zero. None. Zip code is 35459. Right at the Alabama / Mississippi line. Needs aren't that demanding. 10-20mbit/s down and a few mbit/s up will do. We are trying to avoid data caps

-We have Hughes and it sucks worse than VLAN tagging yourself out of a prod switch at 4:50om on a Friday

-AT&T offers wireless plans that are $100 for 100GB. But overages are insane at $20/10GB

-At&t also said they'd do fiber but it's $500/mo minimum and no thanks for a two person office

-UnlimitedVille (I know, I know, but I'm looking at all options) offers unlimited on AT&Ts network for $200/mo but they're hardly..."business" and would require standing up a pole and antennas which is absolutely an option

-CenturyLink offers 20mbit DSL in the area but they say not at this service address. There IS a 4-wire telephone line from the highway to a demarc point at the office. We don't know who's line it is or if it's active. But it runs out to the highway and then along the poles for some distance

Ideally we'd do CenturyLink wireline but ever level 1 sales drone just Google's the address and says "out of service area, can't help you". But we're close so... Maybe I need to talk to their construction Dept?

Any guidance would be appreciated