internet residencial

Got ours last night...6 hours later and boxing the p.o.s up to give it back. 20mbps. Tried EVERY window in our house, when it was at 4 bars the speed was 40mbps, 2 bars and sometimes it would get to 80mbps. Turns out 1 of their towers are down and they don't know when it will be fixed. Plus we asked if trees can interfere and the rep said "Sometimes but we are coming into winter so you shouldn't have to worry about it." HUH??? Ok then what about in the SUMMER?? At 20mbps might as well go back to dial up modems.