What you describe actually sounds pretty good for a WISP. Often speeds are much less than 50Mbps with wireless providers.
Also the fact that they tell you the transmitter on their tower is at capacity (8 connections) is actually a sign of a good ISP. Some WISPs will keep piling on the customers even though their towers are way over capacity, then everyone's connection suffers greatly as a result.
What is your upload speed? I'd wager that's what's really limiting you here.
What you describe actually sounds pretty good for a WISP. Often speeds are much less than 50Mbps with wireless providers.
Also the fact that they tell you the transmitter on their tower is at capacity (8 connections) is actually a sign of a good ISP. Some WISPs will keep piling on the customers even though their towers are way over capacity, then everyone's connection suffers greatly as a result.
What is your upload speed? I'd wager that's what's really limiting you here.